Technical Service-Electronic product solution company-Electronic and electrical product development-Bluetooth design-S

Technical Service

06-27

2023

Bluetooth DONGLE module

The Bluetooth Dongle module is a small module used to add Bluetooth functionality to non-Bluetooth devices. It is usually provided in the form of a USB plug or other interface, and can be connected to non-Bluetooth devices such as computers, TVs, audio equipment, etc., so that it has Bluetooth communication capabilities. Here are the main technical aspects involved:Bluetooth communication technology: The key technology of the Bluetooth Dongle module is the Bluetooth communication technology. It uses the Bluetooth protocol stack to communicate with other Bluetooth devices, including connection establishment, data transmission and control commands, etc. Bluetooth communication technology involves the knowledge of Bluetooth protocol, Bluetooth configuration file, Bluetooth core specification and so on.Radio frequency and antenna design: The Bluetooth Dongle module requires radio frequency design and antenna design to ensure good wireless signal transmission and reception performance. This includes antenna selection, antenna layout, matching circuit design, etc. to optimize RF performance and signal coverage.USB or other interface design: Bluetooth Dongle module usually uses USB interface or other specific interface to connect with non-Bluetooth devices. During the design process, factors such as interface electrical characteristics, signal transmission rate and compatibility need to be considered.Power management and power consumption optimization: Bluetooth Dongle modules usually need to use the device's own power supply or obtain power supply from connected devices. Therefore, power management and power optimization are required to extend battery life or reduce the load on the power supply of connected devices.Driver development and compatibility: In order to make the Bluetooth Dongle module work normally in the operating system, a corresponding driver needs to be developed. This involves driver development and compatibility testing with the operating system.Data Security and Encryption: Data security and encryption in Bluetooth communications are important considerations. The Bluetooth Dongle module needs to support Bluetooth security protocol and encryption algorithm to ensure the security of data transmission and prevent unauthorized access.Software development and API integration: Bluetooth Dongle modules usually need to provide corresponding software development kits (SDK) and APIs so that developers can integrate Bluetooth functions into applications. This includes providing APIs, sample codes and development tools related to Bluetooth communication to simplify the software development process.User interface and configuration tool development: In order to facilitate users to operate and configure the Bluetooth Dongle module, it may be necessary to develop corresponding user interface and configuration tools. These tools can provide functions such as Bluetooth connection management, device pairing, and parameter setting to enhance the user's interactive experience.Compatibility testing and certification: During the development process, compatibility testing is performed to ensure that the Bluetooth Dongle module can communicate and pair normally with various Bluetooth devices. In addition, according to relevant standards and requirements, carry out Bluetooth certification, such as Bluetooth SIG (Special Interest Group) certification, to obtain compliance and approval of Bluetooth technology.Firmware upgrade and maintenance: With the continuous development of Bluetooth technology and the introduction of new functions, it may be necessary to upgrade and maintain the firmware of the Bluetooth Dongle module. This involves the design of the firmware update, transfer and installation process to ensure the latest functionality and performance of the modules.The development and manufacturing process of the Bluetooth Dongle module requires comprehensive consideration of knowledge and technology in multiple fields such as hardware, software, radio frequency and industrial design. Through high-quality engineering practice, comprehensive testing and certification process, a powerful, reliable and stable Bluetooth Dongle module can be developed to provide users with convenient wireless connection and communication solutions.
06-21

2023

Intelligent temperature control fan design

Design of Bluetooth data transmission intelligent temperature control fan systemThe bluetooth data transmission intelligent temperature control fan system designed in this paper is composed of two STC15F2K60S2 single-chip microcomputers as the master controller and slave controller respectively, using the body temperature sensor module as the temperature acquisition device, and the HC-05 master-slave integrated bluetooth serial port module to send and receive fan files Bit information, through the comparison of the system preset temperature and the body temperature detected by the system, the automatic adjustment of the fan motor speed and automatic start and stop are completed, and the operation of the fan motor is controlled through the triode. And display the fan gear, preset temperature, and detected body temperature on LCD1602 at the same time.1. The overall design idea of the intelligent temperature control fan systemUse the body temperature sensing module to collect body temperature and output voltage data to the main controller (STC15F2K60S2) for A/D conversion and calculation, and display the current body temperature value, preset temperature limit and fan gear on LCD1602. The preset temperature limit and the detected current human body temperature can be accurate to two decimal places. Send the gear position to the slave role Bluetooth through the master role Bluetooth, and the speed of the DC fan motor is changed by the controller (STC15F2K60S2) according to the gear position using PWM pulse width modulation. The system preset temperature limit is changed by three buttons, the first one moves the position corresponding to the changed limit value, the second one increases the preset limit value, and the third one lowers the preset limit value.2. Design scheme of Bluetooth intelligent temperature control fan systemThis design uses bluetooth wireless short-distance transmission to intelligently complete the temperature control of the fan motor. By adopting the shift and stop control components with high temperature change resolution and stable performance, the fan motor can automatically change the speed and start according to the change of human body temperature. stop.(1) Selection of temperature sensor: The temperature sensor adopts a body temperature sensing module, which is small in size and only needs one acquisition port to connect to the main controller, plus two positive and negative power supply pins, a total of three pins can work. As long as the human body touches the probe, the module can collect data, and the data can be accurate to two decimal places after the main controller A/D conversion and calculation.(2) Selection of the controller: The controller uses two STC15F2K60S2 single-chip microcomputers as the master controller and the slave controller respectively, through the method of software programming to convert, calculate and compare the body temperature data, and at the same time output the gear through the serial port of the master role Bluetooth Signal. STC15F2K60S2 single-chip microcomputer contains 2048 bytes of random data memory RAM, high performance, low operating voltage, no external crystal oscillator, affordable single chip, suitable for the design system of this article.(3) Selection of display device: This design uses LCD1602 liquid crystal display to display temperature, set limit value and gear position. The liquid crystal display can display 16x02 or 32 characters, the power consumption is extremely low, the displayed data is clear and eye-catching, and the programming of the display program is relatively simple. It can display not only numbers but also characters and even graphics, and the displayed characters are beautiful.(4) Choice of speed regulation method: This design adopts single-chip microcomputer software programming to realize PWM (pulse width modulation) speed regulation method. The most commonly used is the rectangular wave PWM signal. When controlling the speed of the motor, the speed is adjusted by adjusting the duty cycle of the PWM wave. The larger the duty cycle, the faster the speed. By using the software delay method, the high and low level delay time and the cyclic change of the I/O port level are realized to obtain the PWM signal.(5) Selection of wireless transmission devices: The wireless transmitter uses two HC-O5 master-slave integrated Bluetooth modules as wireless transmission devices. This module can set the master-slave mode to connect and send and receive between the master and slave roles. The HC-O5 master-slave integrated Bluetooth module is easy to operate, low power consumption, and the communication distance is within 10 meters, which is suitable for this design.3. Software design of intelligent temperature control fan systemThe program design has two parts, master controller and slave controller.4. Software debugging of intelligent temperature control fan system(1) Debugging of key display: system program written according to this design: the key interface of the program adopts the P2.5, P2.4, P2.3 ports of the main controller, the LCD1602 display data port adopts P0 port, and the RS terminal is connected to P4 .5 port, the RW terminal is connected to the P2.7 port, and the E terminal is connected to the P2.6 port, so as to complete the key function and LCD1602 display. After compiling without errors, and then changing the interface to a simulation debugging interface, the LCD1602 can normally display the upper and lower limits of the preset temperature, the gear position and the temperature given by the program. The button function has also been realized. When the setting key is pressed, the cursor flickers, and when the plus and minus keys are pressed, the number in the blinking cursor can also be added or subtracted by one, and then the setting key is pressed, and the cursor moves to the right (the cursor There are 8 moving positions), modify the upper and lower limits of the temperature.(2) Debugging of the acquisition part of the body temperature sensing module: Due to the integration of the body temperature sensing module, the adjustment is extremely simple. Its high precision, low power consumption, and small size make it possible to achieve high stability and high precision in controlling the motor. The P1.4 port of the main controller is used as the analog input port. Since the input analog signal needs to be converted and processed by AD to display the body temperature, it is necessary to increase the body temperature conversion program. The continuous detection of human body temperature is completed through software program design, and LCD1602 will display the percentile part of the temperature. Connect this module to the circuit, and LCD1602 will display a temperature, but this is not the ambient temperature. In this design, the module can only detect the temperature of the human body. After people pinch their fingers (or touch other parts of the human body) the probe of this module, LCD1602 can display the currently detected human body temperature.(3) Debugging of the fan motor speed regulation circuit: This design uses two triodes to drive the fan DC motor. The software sets the P0.0 port to output different PWM waveforms to the two triodes to drive the rotation of the fan motor. The software is set to output different PWM waves according to different temperatures to obtain different duty ratios to control the fan motor. The larger the duty ratio, the higher the gear. The program realizes the PWM waveform output of the P0.0 port. When the temperature of the human body is lower than the lower limit temperature, the fan will automatically stop rotating (0 gear); ) or start to rotate automatically; when the body temperature is higher than the middle limit and lower than the upper limit, the fan rotates at a medium speed (2 gears); when the human body temperature is higher than the upper limit, the fan rotates at full speed (3 gears).The speed of the fan motor in this design system can be adjusted in four stages, and the speed conversion is completed according to the comparison between the upper and lower temperature limits preset by the system and the temperature detected by the body temperature sensor module. Change the gear information received from the controller in the program, and the fan motor can realize the speed regulation of the corresponding gear.(4) Debugging of the bluetooth circuits of the master and slave roles: the master controller compares the current gear position with the last time. If the gear position changes, it will send the changed gear position to the slave controller through the master role bluetooth. The role Bluetooth receives the gear information sent by the master role Bluetooth, and then transmits it to the slave controller. When there is a gear to the slave controller, the slave controller will output the PWM wave corresponding to the gear. The gear position is generated on the main controller side (can be known through the display of LCD1602), and then use the serial port assistant to connect the slave role Bluetooth to get consistent gear information, and then connect the slave role Bluetooth to the slave controller circuit, and the fan motor will also The corresponding rotational speed can be achieved.5. Hardware debugging of intelligent temperature control fan system5.1 Debugging of key displayThe system button part realizes the following functions: press the setting button to connect the button of the P2.5 port of the main controller, and set the upper and lower limit values of the temperature (the LCD cursor moves and flashes); press the plus button to connect the button of the P2.4 port , to realize the addition of one to the value of the blinking cursor; press the minus key, that is, the button of the P2.3 port, to realize the reduction of the corresponding value by one. If the pressing time is too long, the cursor will not move by one position, but will increase by two positions. The main reason is that the debounce delay time of the key is too long, and the corresponding key debounce delay time can be appropriately increased as an improvement method.This design realizes that the LCD1602 can display the upper and lower limits of temperature, the gear position and the temperature of the human body. The upper and lower limits of the temperature can be adjusted through buttons according to different needs, and the display effect of the LCD1602 is very good and stable.5.2 Debugging of the temperature acquisition part of the body temperature sensor moduleConnect the AD port of the body temperature sensor module to the P1.4 port of the main controller through a square female connector. The four ports on the right side of the main controller are the AD, GND, DC, and VCC ports of the body temperature sensor module. The module can be directly inserted into the header. In order to verify whether the module can work on the main controller board during system debugging, pinch the probe of the module (or other parts of the body) with a human finger, and you can find that the value displayed on the LCD1602 also changes, and it will be when it is stable. Detected body temperature, thus verifying that the module is working properly on the system board. Since the module has only 4 pins, pay attention to the corresponding position of each pin during the debugging process, so as not to reverse the connection and cause the module to fail to work or even burn the module.5.3 Debugging of fan motor speed regulation circuitSince the design of the speed control circuit mainly lies in the software design, the peripheral drive circuit simply amplifies the transmitted PWM signal to drive the fan motor to rotate. When the temperature of the human body is higher than the lower limit of the system preset temperature, the motor starts to rotate. Since the temperature of the human body is relatively constant and does not change much, the gear position of the fan motor will not change too frequently. The speed of the fan will change as the gear is switched. When the fingers (other parts of the body) leave the probe of the body temperature sensing module, it is found that the detected temperature first increases and then decreases until it becomes stable. system performance.6. Intelligent temperature control fan system function(1) Functions realized by the system: This design can realize the single-chip microcomputer system to detect the change of human body temperature, and according to the change of body temperature, transmit the gear signal through wireless Bluetooth to control the start-stop and speed regulation of the fan DC motor. Different duty ratios are output by the single-chip microcomputer to generate different speeds; different temperature upper and lower limits can also be preset through the buttons, and then the gear is adjusted according to the comparison between the set temperature limit and the detected human body temperature to control the motor speed . When the body temperature is lower than the lower limit of the preset temperature, the motor stops rotating; when the body temperature is higher than the lower limit of the preset temperature, the P0.0 port of the single chip microcomputer outputs PWM signals with different duty ratios to regulate the speed of the fan. The system can also dynamically display the current human body temperature, set temperature limit and gear.(2) System function analysis: The system is generally composed of two parts: the main controller side and the slave controller side. The main controller side is composed of five parts, namely the main controller (single chip microcomputer), LCD1602 display circuit, body temperature detection module body temperature acquisition circuit, independent button circuit, master role Bluetooth connection circuit; the slave controller side is composed of three parts, that is, the slave role Bluetooth connection circuit, slave controller (single chip microcomputer), fan motor speed regulation circuit. The body temperature acquisition circuit in the human body temperature detection module is the most important part of the whole design system. First of all, the body temperature must be detected, and the gear can be obtained by comparing the master controller with the temperature limit, and the slave controller controls the speed of the DC fan motor through the gear signal; then the master and slave role Bluetooth connection circuit, this part uses the master Communication between roles from Bluetooth. The gear position signal of the master controller is sent to the slave role Bluetooth through the master role Bluetooth, and then transmitted to the slave controller; the second is the fan motor drive circuit, which amplifies and outputs the PWM wave output from the controller through the peripheral circuit. Different PWM wave to get different motor speeds. The circuit design uses two triodes to achieve a better control effect; finally, the dynamic display circuit of LCD1602 realizes the display of the set temperature limit, human body temperature and fan motor gear, and there are independent buttons to realize the temperature limit according to different needs. Adjustment.SummarizeThe designed system uses single-chip microcomputer as the control element, and the gear position is obtained according to the comparison between the human body temperature detected by the body temperature sensor module and the set temperature limit value, and the gear position is transmitted through wireless transmission between Bluetooth, and the fan is realized within a certain distance. Speed adjustment. The design of this system can be extended to the fan motor control system of the family to realize the intelligent control and adjustment of the fan speed, and also realize the monitoring of human body temperature (especially for children and the elderly).The above is the design scheme of the Bluetooth data transmission intelligent temperature control fan system introduced by Shenzhen Zuchuang Microelectronics Co., Ltd. If you have Bluetooth product design and development needs, you can trust us. We have rich experience in custom development of smart electronic products. We can evaluate the development cycle and IC price as soon as possible, and can also calculate the PCBA quotation. We are a number of chip agents at home and abroad: Songhan, Yingguang, Jieli, Ankai, Quanzhi, realtek, with MCU, voice IC, BLE Bluetooth IC, dual-mode Bluetooth module, wifi module. We have hardware design and software development capabilities. Covering circuit design, PCB design, single-chip microcomputer development, software custom development, APP custom development, WeChat official account development, voice recognition technology, Bluetooth development, wifi technology, etc. It can also undertake the research and development of smart electronic products, the design of household appliances, the development of beauty equipment, the development of Internet of Things applications, the design of smart home solutions, the development of TWS earphones, the development of Bluetooth earphone speakers, the development of children's toys, and the research and development of electronic education products.
06-20

2023

Bluetooth iBeacon and Mesh

Bluetooth iBeacon and Mesh networking technologyThe main content of this article is to analyze the iBeacon broadcast technology of BLE from the principle and protocol, and introduce the Mesh ad hoc network technology of Bluetooth low energy, so as to break the bottleneck that traditional Bluetooth cannot ad hoc network or weak networking function.1. Bluetooth iBeaconThere are two forms of signals sent by BLE, namely broadcast and connection. iBeacon technology is a BLE-based intermittent broadcast technology proposed by Apple, namely Internal beacon.1.1 Analysis of iBeacon data structureThe data volume of a BLE broadcast frame can reach up to 47 bytes, which includes a 1-byte header, 4-byte address, 39-byte broadcast channel PDU data packet, and 3-byte CRC check code:The iBeacon broadcast technology adopts the simplest broadcast data format, which deletes the data header and MAC address in the PDU data packet, and only sends 31 bytes of data; when this topic is studying iBeacon broadcast, set its data format to 6 bytes preset data, 1-byte manufacturer data, 2-byte company service code, 16-byte 128-bit UUID, 2-byte major device number, 2-byte minor device number, 1-byte signal emission strength, In addition to the preset position data, the data in other fields can be modified by yourself. The mobile terminal can receive the iBeacon broadcast signal sent by the BLE base station, and capture iBeacon data through software.1.2 Analysis of RSSI characteristics of iBeaconiBeacon technology uses intermittent radiation broadcast data into the space, so the spatial RSSI network distribution is changing according to certain rules. In this project, the broadcast interval is set to ±=1095 msmsT, that is, under the condition of constant environmental factors, the RSSI network Take T as the time interval to make periodic changes. There are two ways to measure signal strength in real-time communication: RX and RSSI, both of which are measures of the received power of the signal by the antenna, but the former measures the power of the signal in milliwatts; while RSSI indicates the received signal strength The percentage of is a relatively comparative measurement method, and the comparison standard is defined by the chip manufacturer.2. Bluetooth Mesh Ad Hoc NetworkCompared with ZigBee, traditional Bluetooth devices have poor ad hoc network capability, which is one of the reasons why it is difficult to implement large-scale Internet of Things; with the rapid development and popularization of BLE technology, this project proposes that the ad hoc network based on Bluetooth Mesh will Break through the defects of traditional Bluetooth and complete the cross-island connection of Bluetooth Mesh.2.1 Traditional Bluetooth device networkA piconet is a traditional Bluetooth network topology. There can only be one master device in a piconet, and less than or equal to seven slave devices in wake state. The master-slave device communicates with the slave device according to polling rules, and the communication between the slave devices requires the master device to be bridged; a single piconet adopts a star topology, and multiple piconets are linked together to adopt a tree topology , its principle conforms to the allocation model of 1 master and 7 slaves, that is, the piconets are interconnected in the form of crossover; the slave node 4 of network A is the master node of network B, so many piconets constitute a scatternet (scatternet) as shown in Figure 5.5 shown. The disadvantage of the scatternet is that the structure is complex and redundant. Two adjacent slave nodes that are not in the same network need to exchange information in the form of multiple hops, and the transmission speed is slow, resulting in waste of resources.2.2 Bluetooth Mesh Ad Hoc NetworkEach node in the wireless Bluetooth Mesh network uses multi-hop technology to access the ad hoc network. There are one or more routes between two device nodes, and data communication is carried out in a cooperative manner. The Bluetooth iBeacon signal removes the size of the packet header, and the real information carried by each frame is 31 bytes. The wireless Mesh network itself is a high-capacity, high-speed network. Wireless communication is very efficient. In theory, a Bluetooth wireless Mesh network can connect 65,535 device nodes. In actual experiments, limited by factors such as the CPU and memory capacity of the device, the number is more than 200, and the transmission distance of each device node is greater than 50 meters. For large networks, it can Connect through multiple ad hoc networks.In the application of BLE, the Mesh ad hoc network realizes the mutual communication between each device node, abandons the concept of one master device pairing seven slave devices in the piconet, and the cooperative communication broadens the channel of data interaction in the system.The links between each device node are connected to each other to form a dense network. Among them, the dotted line indicates that two device nodes complete indirect data communication by bridging through intermediate nodes. The form of signal transmission is like the recursion of waves. . In a Mesh network, there are two reasons for indirect data communication: for example, the dotted line m is because the distance between device nodes is greater than the maximum distance of Bluetooth signal propagation; the dotted line n is non-line-of-sight communication, and there are Bluetooth signals between device nodes Obstacles that cannot be passed through.2.3 Related Protocols of Bluetooth Mesh Ad Hoc Network(1) Coordinated allocation of channels: When the Bluetooth multi-channel is connected to the Mesh ad hoc network, each iBeacon device node can only monitor one available channel at a time, and the device node can ensure the signal sent by each node through a specific negotiation mechanism. On the same channel, that is, device nodes can switch from different channels to available channels in real time; the research uses the ATIM window multi-channel synchronization mechanism, and its principle is: at the beginning of the window, all device node signals are forcibly switched to the same channel.The channel division of the Mesh network is to allocate the network's use of channels from the division of frequencies to ensure the high efficiency of the Mesh network; among them, the mainstream channel allocation scheme is the division of groups, and the allocation rule is to select the one with the least conflict between adjacent nodes. channel.(2) Network search and routing and forwarding: Network search technology is used to discover iBeacon nodes in the Mesh network and establish a node information database. The main methods used are: scanning of network information and maintenance of node information database; For new devices in the network, the node information of the device will be propagated in the Mesh network in the form of routing and forwarding. The routing and forwarding technology directly affects the utilization rate of the network. The Mesh network adopts a multi-hop technology, that is, the signal can be received by the target node through multiple node hops; there are three points to consider when selecting the route: 1. Comprehensive consideration of the routing Selection, the minimum number of hops is not the only criterion for judging the best route. 2. Improve the fault tolerance of Mesh network routing to avoid signal transmission failure caused by link interruption. 3. Improve resource utilization and choose multiple routes; the mainstream Mesh network The network routing protocol is a dynamic source routing protocol, which is a symmetric reactive ad hoc routing protocol.(3) Network security: Mesh network's unique multi-hop technology and self-organizing network technology ensure the security of Mesh network; at the same time, in order to solve the confidentiality of node traffic in Mesh network, the control and supervision of iBeacon node network access, Mesh security Association proposes a security architecture with Mesh keys as the core; in which only authenticated keys can organize communication, the authentication process has 3 steps: 1. Link management protocol interaction phase, 2. EAP authentication, 3. Mesh 4-way handshake for security associations. Therefore, when establishing a Mesh network in this project, the network key is pre-set.The way to realize the Mesh ad hoc network is: the application software of the mobile terminal searches and finds the iBeacon broadcasting device, and establishes a link, selects the security configuration menu, sets the security key of the Mesh network, switches to the device search menu, and selects the corresponding device in the information list Access to the network and establish a Mesh ad hoc network with mobile terminals as MP nodes. Here is a network security issue. A BLE device can be used as an intermediate bridge for information transmission in a Mesh network, but it can only have one network key at the same time, that is, it can only be controlled by one MP node.SummarizeThis paper mainly introduces the iBeacon technology of low-power Bluetooth, analyzes the iBeacon signal data structure, and supplements the RSSI characteristics of the signal, and uses the logarithmic path loss model to express the relationship between the signal strength value received by different chips and the signal propagation distance; then This paper compares and analyzes the traditional Bluetooth networking technology (piconet) and Bluetooth Mesh ad hoc networking technology, and describes the Bluetooth Mesh protocol and its implementation from three aspects: channel coordination and allocation, network search and routing forwarding, and network security.The above are the details of the Bluetooth iBeacon and Mesh networking technology introduced by Shenzhen Zuchuang Microelectronics Co., Ltd. If you have Bluetooth product design and development needs, you can trust us. We have rich experience in custom development of smart electronic products. We can evaluate the development cycle and IC price as soon as possible, and can also calculate the PCBA quotation. We are a number of chip agents at home and abroad: Songhan, Yingguang, Jieli, Ankai, Quanzhi, realtek, with MCU, voice IC, BLE Bluetooth IC, dual-mode Bluetooth module, wifi module. We have hardware design and software development capabilities. Covering circuit design, PCB design, single-chip microcomputer development, software custom development, APP custom development, WeChat official account development, voice recognition technology, Bluetooth development, wifi technology, etc. It can also undertake the research and development of smart electronic products, the design of household appliances, the development of beauty equipment, the development of Internet of Things applications, the design of smart home solutions, the development of TWS earphones, the development of Bluetooth earphone speakers, the development of children's toys, and the research and development of electronic education products.
06-19

2023

Bluetooth anti-jamming technology

1. Bluetooth adaptive frequency hopping (AFH) technologyThe Bluetooth system works in the 2.4GHz ISM (ie industrial, scientific, medical) frequency band. Many devices work in this frequency band. Working in such a frequency band, mutual interference must be relatively serious. Therefore, the Bluetooth system uses frequency hopping technology to prevent fading and Suppress distractions. Before the connection is established, the Bluetooth device selects a frequency hopping frequency in a fixed frequency band, quickly exchanges time and address handshake information, and then quickly obtains time and frequency synchronization. After the connection is established, the two devices change the channel frequency according to the hopping sequence, so that the frequency hopping frequency appears random.Bluetooth defines 32 frequency points as a frequency band, which is divided into 79 sub-frequency bands. The lowest 28 bits of the Bluetooth master clock CLK and the master device address determine the frequency band and frequency hopping sequence of Bluetooth work, as shown in Figure 2.10; Bluetooth system definition Frequency hopping sequences under 5 working states: paging, paging response, inquiry, inquiry response and connection frequency hopping sequence. There are different strategies to generate frequency hopping sequence in different states.Figure 2.11 shows the generation principle of the frequency hopping sequence of the Bluetooth system; the input X is determined by the clock information bit, which determines the phase of the hopping frequency point in the 32 frequency sequences of a certain frequency band -- the offset of the frequency sequence in the segment At the same time, the speed of changing the frequency hopping frequency point is also determined by it; A to F determine the order of the frequency hopping sequence. value; in the query/paging scanning state, the input sequence from A to F is only related to the address, so its frequency hopping sequence is uniquely determined. In other states, A~F is controlled by the clock and the Bluetooth address, and its frequency hopping The sequence jumps accordingly with the change of the clock; Y1 and Y2 control the selection of the transceiver frequency hopping sequence, Y1 ensures that the transceiver frequency will not be repeated, and Y2 makes the transceiver frequency in different frequency bands; PERM5 is a The butterfly arithmetic unit controlled by C, D, and Y1 plays the role of disturbance.(1) Paging/paging scanning state: Bluetooth devices search for other devices to join their piconets through paging; paging devices select a new frequency hopping point every 312.5µs to initiate paging, during paging scanning, The paged device selects a new frequency point to monitor every 1.28s. The paging and the paged device use the lower 28 bits of the paged device address. The paging hopping sequence generated is a well-defined periodic sequence, which The 32 frequency points are evenly distributed on 79 frequency channels.(2) Query/query scanning status: Bluetooth devices search for other devices around by querying. The querying device selects a new frequency to send query messages every 312.5µs, and the queried device selects a new frequency to monitor every 1.28s; query Use the universal inquiry access code as the inquiry address with the inquired device. The generated 32 query hopping sequences are evenly distributed on 79 frequency channels.(3) Connection state: Using the lowest 28 effective bits of the master device address, the two sides of the Bluetooth communication device change a frequency every 625µs, and the resulting channel hopping sequence period is very long, and 79 hopping sequences are in any short period of time It is close to the uniform distribution, which can meet the requirements of the frequency hopping system.The algorithm of adaptive frequency hopping is added in the Bluetooth 1.2 protocol; when a certain channel signal quality is found to be poor during Bluetooth communication, that is, it becomes a "bad" channel, these bad channels can be discarded during frequency hopping and other channels can be selected Frequency hopping channels with good quality are used instead, thereby avoiding communication interference on certain frequency points, thereby enhancing its anti-interference ability.2. Bluetooth baseband error correction mechanismBluetooth technology adopts forward error correction FEC and automatic repeat request (Automatic Repeat-reQuest, ARQ) technology, and the error correction mechanism adopted is relatively simple. Among them, the forward error correction (FEC) is that the sending end encodes the data information according to certain rules to form a code with error correction capability; the receiving end receives the encoded data and performs corresponding decoding according to the predetermined rules to determine the received data. Whether there is an error in the data information, if there is an error, determine its location and correct it. This coding method is more suitable for real-time transmission systems, but the disadvantage of this technology is that the error correction capability is limited.Autonomous retransmission request is also called decision feedback. It uses confirmation and timeout to realize reliable information transmission on the basis of unreliable service; The error detection capability; after receiving the encoded information, the receiving end decodes it and makes a judgment to detect whether there is a certain bit error, and then sends the judgment result back to the sending end through the feedback channel; the sending end according to the feedback judgment result, Decide whether to retransmit the data; but the retransmission is not unlimited. After multiple retransmissions, the system will not retransmit after the time specified by the system.The specific error correction methods in the Bluetooth baseband include: 1/3 ratio FEC, 2/3 ratio FEC and ARQ. Among them, the 1/3 ratio FEC codes each bit of information three times, the coding method is relatively simple, and the length of the coding sequence is three times the length of the original sequence. The 2/3 ratio FEC encoding uses a generator polynomial to encode 10-bit data into 15 bits, which is a (15, 10) truncated Hamming code, and the data receiver performs the corresponding reverse operation, according to the error detection and error correction mechanism provided by the algorithm restore the original data. In the ARQ mode, the data packet has been retransmitted until the final acknowledgment is received or the retransmission times out.The above are the details of the Bluetooth anti-interference technology introduced by Shenzhen Zuchuang Microelectronics Co., Ltd. for you. If you have Bluetooth product design and development needs, you can trust us. We have rich experience in custom development of smart electronic products. We can evaluate the development cycle and IC price as soon as possible, and can also calculate the PCBA quotation. We are a number of chip agents at home and abroad: Songhan, Yingguang, Jieli, Ankai, Quanzhi, realtek, with MCU, voice IC, BLE Bluetooth IC, dual-mode Bluetooth module, wifi module. We have hardware design and software development capabilities. Covering circuit design, PCB design, single-chip microcomputer development, software custom development, APP custom development, WeChat official account development, voice recognition technology, Bluetooth development, wifi technology, etc. It can also undertake the research and development of smart electronic products, the design of household appliances, the development of beauty equipment, the development of Internet of Things applications, the design of smart home solutions, the development of TWS earphones, the development of Bluetooth earphone speakers, the development of children's toys, and the research and development of electronic education products.
06-18

2023

ZigBee wireless technology

1. Brief introduction of ZigBee technologyMany scenarios in the home and industry require extensive use of wireless control and monitoring, and these requirements often require low data transfer rates, long battery life, and low complexity of use. In order to meet these requirements, IEEE proposed a wireless standard IEEE802.15.4, which is also called ZigBee. ZigBee is a wireless communication protocol for short distances and low data rates. It has three operating frequency bands, and the 2.4GHz frequency band is mainly used in China. ZigBee has the following characteristics: (1) low power consumption; (2) providing a complete wireless mesh network; (3) a single network can connect up to more than 65,000 devices; (4) easy to deploy; (5) economical, price Inexpensive; (6) Uses smaller data packets than other wireless technologies.2.ZigBee network topologyThe ZigBee standard specifies two types of devices: thin and full-featured. The former has limited functions, while the latter has all functions, and the latter can also be configured as an arbitrary function device. A reduced-function device can only communicate with a full-function device on the network, while a full-function device can communicate with any device. Reduced-function devices are used to perform relatively simple tasks, such as switches that turn functions on or off. Reduced-function devices generally have less memory size and processing power than full-featured devices.The ZigBee standard stipulates that there are three functional devices in the ZigBee network: a router, a coordinator and a terminal device. As the core device in the network, the coordinator is a full-featured device that forms the root of the network through which it can connect to other networks. There is only one coordinator in each ZigBee network. ZigBee networks are initially created by the coordinator, which stores information about the network and acts as a repository for security keys. Routers route data from other devices in a ZigBee network. Routing is the processing of the path along which data is forwarded to a destination device. ZigBee end-devices can connect with a coordinator or router to join the network, but cannot relay data. This feature allows end-device nodes to be inactive most of the time, thereby extending battery life.A ZigBee network composed of devices with different functions can have three topologies: star, tree and mesh, among which tree and mesh networks belong to peer-to-peer networks.In a tree network, the coordinator acts as the root of the tree, routers or end devices can connect to the coordinator, and it can be expanded like a tree. End devices cannot have child nodes because they cannot relay information. This topology allows multiple levels of nodes in the network, and terminal devices can directly join the network through routers without relying on the coordinator, and all messages can be sent to any other device through routing. This type of topology is the most reliable one for ZigBee devices to communicate with other devices on the network.The star network takes the coordinator as the center, and multiple terminal devices are directly connected to the coordinator, which is the simplest network. When using this structure, the terminal device can only communicate directly with the coordinator, and the communication between two terminal devices requires the coordinator to forward messages, and the coordinator acts as a router. Therefore, the data flow through the coordinator in the star network is relatively large, and the more network nodes, the lower the communication efficiency of the entire network.Figure 3-1 Three topological structures of ZigBee networkMesh topology is the most flexible and widely applicable topology. In a mesh network, it allows the network to search for alternate paths for messages, where there are multiple paths a message can take from its origin to its destination. Therefore, message delivery is very reliable and has low latency in a mesh network.No matter which structure is used, the ZigBee network is created by the only PAN (PersonalAreaNetwork, personal area network) coordinator. The coordinator manages the entire network and is responsible for the following tasks: (1) start, terminate, or route messages across the network; (2) assign 16-bit or 64-bit network addresses to devices that later join the network; (3) generate the network Corresponding PAN identifier (PANID), each PANID corresponds to a different ZigBee network, PANID allows devices in the network to use 16-bit short addresses to communicate with other devices in the entire network. The PAN coordinator generally has a long active period, so it is usually powered by a mains power supply, and other devices are usually powered by batteries. The smallest ZigBee network contains only one end device and one PAN coordinator.3. ZigBee protocol stackAs can be seen from Figure 3-2, the structure of the ZigBee protocol stack has four layers, of which the physical layer and media access control layer are defined by the IEEE802.15.4 standard, and the network layer and application layer are defined by the ZigBee Alliance.3.1 Application layerThe APL layer of ZigBee consists of three parts: Application Support Sublayer (APS), Application Framework (AF) and ZigBee Device Object (ZDO). APS provides the interface between the network layer and the application layer, and its main functions are: (1) maintaining the binding table; (2) transmitting messages between the binding devices; (3) managing group addresses. AF is an environment that hosts application objects to control and manage the application layer. The application object is developed by the manufacturer, which can customize the application for the device, and has a uniquely identified endpoint number (endpoint 1 to endpoint 240). A single device can have up to 240 application objects. The ZigBee device object is the interface between APS and AF. ZDO is responsible for initializing APS, network layer and security service specifications. Its main functions are: (1) Define the role of the device in the network: coordinator, router or terminal device; (2) Discover devices and applications on the network, start or bind them accordingly (3) Perform relevant security tasks.3.2 Network layerThe network layer is responsible for managing the formation, joining, leaving and routing maintenance of the network. The network layer also supports management services and data services. The data is transmitted by the corresponding data entity and can be accessed through the network layer data entity service access point. The management service is in charge of the corresponding management entity, which can provide network layer management service for the application layer through the management entity service access point of this layer.The network layer of the coordinator creates a ZigBee network and assigns network addresses to devices that join the network afterwards. The distance (hops) of each frame of data transmitted in the network is specified by the network layer. The coordinator can enable security functions at the network layer - using a 128-bit AES encryption key to encrypt network data, new devices that join the network created by the coordinator can communicate with other devices on the network only after the key is distributed communication.In general, the network layer is responsible for the following functions: (1) joining or leaving the network; (2) providing AES encryption; (3) discovering and maintaining routes between devices; (4) routing functions, except for terminal devices; (5) ) Configure the device as a device with different functions: coordinator, router or terminal device; (6) discover neighbors who can communicate without routing and maintain the neighbor table; (7) assign addresses to new devices that join the network, only applicable to Coordinator and router.3.3 MAC layerIn the MAC layer, the MAC management object is responsible for the MAC layer management service, and the MAC layer provides a service interface to the network layer through the MAC management object access point. The MAC layer specifies four types of frames: MAC command frames, response frames, data frames, and beacon frames. Wherein, the beacon frame is a beacon sent by the coordinator, and is used to synchronize all devices in the same network to the beacon. The data frame is used to send valid data, the response frame is used to confirm the receipt of the data frame, and the MAC command frame is dedicated to sending MAC commands.The MAC layer uses a special channel access mechanism to support multiple devices using the same channel to communicate with each other, that is, carrier sense multiple access with collision avoidance (CSMA-CA). In CSMA-CA, a device listens on a channel to ensure that the channel is free before sending a message. If the channel is occupied, it cancels the transmission and retries after a random amount of time until the maximum number of retries is reached or the channel becomes idle.The main functions of the MAC layer are: (1) Provide security functions of this layer; (2) Manage channel access; (3) Use CSMA-CA channel access; (4) Synchronize the device with the beacon (in the network using the beacon); ( 5) Generate beacons (coordinator only); (6) Provide disassociation and association functions in the network; (7) Establish reliable links between peer devices.3.4 Physical layerThe physical layer is the lowest layer of the protocol stack, which is closest to the hardware. The main functions of the physical layer include: directly transmitting data; selecting a communication channel; listening to the channel to determine whether it is idle; detecting signal energy; controlling the switch of the wireless transceiver; detecting link quality; data modulation and resolution Tune. The physical layer also provides management services and data services. The management service is to manage the relevant data of this layer through the database; the data service is to encapsulate and send data packets or receive and analyze data packets when communicating with other ZigBee devices.4. ZigBee data transmission methodZigBee equipment can use the channel in two ways: contention or no contention. In the competition mode, all devices in the network use the CSMA-CA mechanism to send messages, and the first to find an idle channel transmits data first. In the non-contention mode, the PAN coordinator allocates time for other devices to send messages, that is, guaranteed time slots. The device does not need to listen to the idle state of the channel to send data during the guaranteed time slot. The coordinator keeps devices in the network synchronized through beacons, providing guaranteed time slots. There are three ways of data transmission in IEEE802.15.4: (1) from peer device to peer device; (2) from device to coordinator; (3) from coordinator to device.4.1 Data transfer between peer devicesIn a peer-to-peer network all devices are usually synchronized and any device can communicate with each other. In a mesh network, there are multiple optional routes for data from the sender to the receiver. If the original route cannot be used due to environmental changes, the devices in the network cooperate to find an alternative route. This ability to dynamically create and modify routes increases the reliability of data transfers.4.2 Data is sent to the coordinatorIn a beacon-enabled network, devices periodically synchronize their clocks via beacons. If it is not in the guaranteed time slot, the device uses the CSMA-CA method to send data to the coordinator. The timing diagram is shown in Figure 3-3(a). Figure 3-3(b) shows the process of data being sent to the coordinator in a network without beacons enabled, and the device will send data as soon as it detects that the channel is free. Only when the device needs it, the coordinator will reply with an acknowledgment message to indicate receipt of the data.4.3 Send data from the coordinatorFigure 3-4(a) illustrates the process of sending data from a coordinator to a receiving device in a beacon-enabled network. First, the coordinator will remind the receiving device that there is data to be transmitted in the beacon. After receiving the beacon, the receiving device sends a data request to the coordinator, indicating that it is ready to receive data. After receiving the data request message, the coordinator replies with an acknowledgment and sends the data to the target device. When the receiving device receives the data, it replies with an acknowledgment as needed.In a network that does not support beacons, the coordinator will cache data and wait for the receiving device to actively request data. If the coordinator has no data cache, it sends a data message with a specially formatted acknowledgment reply or a zero-length payload, indicating that there is no data to send.The above are the details of ZigBee wireless communication technology introduced by Shenzhen Zuchuang Microelectronics Co., Ltd. for you. If you have Bluetooth product design and development needs, you can trust us. We have rich experience in custom development of smart electronic products. We can evaluate the development cycle and IC price as soon as possible, and can also calculate the PCBA quotation. We are a number of chip agents at home and abroad: Songhan, Yingguang, Jieli, Ankai, Quanzhi, realtek, with MCU, voice IC, BLE Bluetooth IC, dual-mode Bluetooth module, wifi module. We have hardware design and software development capabilities. Covering circuit design, PCB design, single-chip microcomputer development, software custom development, APP custom development, WeChat official account development, voice recognition technology, Bluetooth development, wifi technology, etc. It can also undertake the research and development of smart electronic products, the design of household appliances, the development of beauty equipment, the development of Internet of Things applications, the design of smart home solutions, the development of TWS earphones, the development of Bluetooth earphone speakers, the development of children's toys, and the research and development of electronic education products.
06-17

2023

Bluetooth topology networking

Bluetooth topology networking technology solutionDeepening teaching reform and making teaching more interactive is one of the important goals of the development of educational technology, and it is also the embodiment of the value of modern technology in educational reform. On the one hand, in the traditional teaching, the class teaching system is used to divide students, and there are differences in the level of students, so it is difficult to meet the requirements of teaching students in accordance with their aptitude.On the other hand, the traditional teaching mode separates the knowledge content from the real and rich situational relationship it produces, resulting in subjective passive learning and stagnant knowledge, which is not conducive to effectively building a complete knowledge system and innovation. Traditional education adopts the cramming education method, and students cannot obtain perceptual and diversified learning modes, and the interaction between teachers and students, and between students and students is very poor. Therefore, attention should be paid to the improvement of experimental methods and technologies, and new educational models such as interactive education, independent choice of courses and learning environments should be widely adopted and accepted. The combination of wireless network education and traditional campus network shows people a brand-new and broad learning level, breaking through the shackles of traditional education methods, as long as there is a digital terminal and equipment connected to the network, learning can be carried out anytime and anywhere and training. The bluetooth technology that appears in the field of wireless communication can transmit data such as voice, image and text synchronously, and is an effective technology for realizing wireless network education.Bluetooth (Bluetooth) is a short-range wireless communication technology standard jointly formulated by five companies including Ericsson, IBM, Intel, Nokia, and Toshiba in 1995. Its purpose is to achieve a maximum data transmission rate of 1Mb/s and a maximum transmission distance of 10m. Wireless communication. The Bluetooth operating frequency is the 2.4GHz ISM (Industrial, Scientific, Medical) frequency band commonly used in the world, so there is no need to apply for an applicable license from the Federal Communications Commission (Federal Communication Commission) or any international regulatory agency. Bluetooth products communicate with the Internet, so that devices between classrooms and offices, and between student data terminals and campus networks can be interconnected without cables, greatly improving office and communication efficiency.1. Introduction to Bluetooth TechnologyBluetooth is an open low-cost, short-range wireless connection technology specification for transmitting voice, image and text data between different devices. As a standard for short-range wireless interconnection between fixed electronic devices and portable electronic devices, Bluetooth replaces cable connections. Its main features are stable work, simple equipment, low power, little harm to the human body, and low price. Bluetooth technology is mainly oriented to various voice and data devices in wireless networks. It connects them into a piconet by means of wireless communication, and multiple piconets can also be interconnected into a distributed network, so that various devices can be realized conveniently and quickly. communication between. A communication device with Bluetooth function can establish a connection within a certain distance, thereby establishing a temporary personal wireless network. The Bluetooth technology wireless transceiver is a very small chip, about 9mm×9mm, which can be easily embedded into any fixed or portable device, easy to install, does not affect the appearance of the device, and has high practicability and operability. Bluetooth technology supports point-to-point and point-to-multiple communications. The principle of implementation is that a Bluetooth device relies on a dedicated Bluetooth chip to send radio signals within a short distance to find another Bluetooth device. Once found, the device starts to communicate.The characteristics of Bluetooth technology mainly include: ①The short-range Bluetooth wireless communication distance is 10m, which saves battery power; ②The wireless transceiver chip with low power, small size and low cost is only 0.5 square inches; ③Use simple link layer protocol and binary The frequency hopping technology further reduces the complexity and cost of the radio frequency chip; ④Bluetooth technology provides a standard rate of 1Mbit/s for the piconet; ⑤Using an additional power amplifier can extend the wireless communication distance to 100m. Within a Bluetooth range, multiple independent piconets can exist. These piconets form a distributed network so that more Bluetooth devices can be activated and combine to provide higher bandwidth.2.The structural characteristics of the Bluetooth technology systemLike OSI (Open System Interconnection), a layered approach is used in the protocol architecture of the Bluetooth technology standard, and its purpose is also to make applications interoperable. If the application programs of the remote device run on the same protocol stack, they can communicate with each other, and different application programs can use different protocol stacks. The Bluetooth protocol stack uses the common Bluetooth data link layer and physical layer protocols.The Bluetooth core protocol is a protocol unique to the Bluetooth technology standard, developed by the SIG (Bluetooth Special Interest Group). Bluetooth devices must support the Bluetooth wireless interface and core protocol, while other protocols can be selected according to specific circumstances, mainly including Logical Link Control and Adaptation Protocol (L2CAP), Service Discovery Protocol (SDP), and baseband protocol and link Management Protocol (LMP).(1) Baseband protocol. It is mainly responsible for establishing the physical radio frequency link between each bluetooth device unit in the micro network, that is, controlling the synchronization and transmission of the frequency hopping sequence. Because the Bluetooth radio frequency system uses frequency hopping spread spectrum technology, that is, frequency hopping is performed at a rate of 1600 hops/second on the 2.4GHz frequency band to realize information transmission and reception. A packet is meant to be sent at a specified time and at a specified frequency. The frequency hopping technology mainly divides the frequency band into several frequency hopping channels. On this layer, the clocks and transmission hopping frequencies of different Bluetooth devices are synchronized through paging and inquiry processes.(2) Link Management Protocol (LMP). It is mainly responsible for the control and establishment of the link between Bluetooth devices, as well as the negotiation and control of the size of the baseband group. It is mainly responsible for the completion of device link quality management, device power management, data packet management, link control management and link security management, etc. five tasks. It conducts authentication and encryption through connection initiation, exchange and verification, and determines the baseband data packet size through negotiation. The user of the device with Bluetooth function can set and control the link status of the remote Bluetooth device and the local Bluetooth device through the link manager, and then realize the management of the link.(3) Logical Link Control and Adaptation Protocol (L2CAP). The logical link control and adaptation protocol supports secondary multiplexing of high-level protocols, reassembly and segmentation of packets, and quality of service. It belongs to the underlying Bluetooth transmission protocol, which mainly focuses on the realization of wireless communication of data and voice data on the physical link. It is an adaptation protocol that shields the baseband protocol for the high-level transport layer and application layer protocols. The protocol allows high-level protocols and applications to send and receive data as long as 64K bytes. The Logical Link Control and Adaptation Protocol only supports asynchronous connectionless (ACL) links.(4) Service Discovery Protocol (SDP). The service discovery protocol plays a very critical role in the Bluetooth technology framework and is the basis of all user models. In the Bluetooth device network environment, the discovery of local devices and the use of services and functions provided by remote devices to provide their own services to other Bluetooth devices are also the main way of network resource sharing and the problem that SDP needs to solve. Device information, service characteristics and service types can be queried through the service discovery protocol. Users can select one of the available proximity services to establish a connection between two or more Bluetooth devices.Bluetooth supports packet switching and circuit switching technologies, and defines two types of links, namely connectionless asynchronous link (ACL) and connection-oriented synchronous link (SCO). Each link supports 16 different packet types, 4 of which are used for control packets.3. Application of Bluetooth network topology in modern universitiesThe modern university network designed based on Bluetooth technology must first solve the division of the network structure, so choosing an appropriate network topology has become the key to setting the network structure. Devices in the network are generally divided into master devices and slave devices. The clock and frequency hopping sequence of the master device are used to synchronize all other devices, namely slave devices. The device that performs paging and establishes a connection is defaulted as the master device connected to the network, and the device in the network that is synchronized with the clock and frequency hopping sequence of the master device is the slave device. Since the Bluetooth standard supports both point-to-point and point-to-multipoint connections, multi-networks can be established as required, and then multi-network connections can be made into a topology map of a scatternet.Due to the ease of use and high aggregation of the Bluetooth network, the wireless network structure of colleges and universities can be realized according to different network topologies. A typical Bluetooth-based wireless network takes the Internet network management center as the core, and the management center provides a wired network to each functional server. Users can access the corresponding server through the wireless access node of the server through digital terminal devices with Bluetooth functions such as smartphones, laptops, and PDAs. No matter when and where, as long as there is wireless network coverage, they can access the corresponding information.SummarizeAccording to different Bluetooth wireless network access methods, different wireless network-based solutions can be constructed. At present, point-to-point applications and wireless access points are mainly used. The construction of Bluetooth wireless network in colleges and universities is developed with the rapid development of computer network technology and modern communication technology. Wireless network is not a ban on wired network, but a functional expansion of it. Although there are problems in some technical details of Bluetooth, the integration of Bluetooth components, and the price, with the continuous development of technology, the application prospects of Bluetooth-based wireless networks in colleges and universities will be broader.The above are the details of the development of Bluetooth technology introduced by Shenzhen Zuchuang Microelectronics Co., Ltd. for you. If you have Bluetooth product design and development needs, you can trust us. We have rich experience in custom development of smart electronic products. We can evaluate the development cycle and IC price as soon as possible, and can also calculate the PCBA quotation. We are a number of chip agents at home and abroad: Songhan, Yingguang, Jieli, Ankai, Quanzhi, realtek, with MCU, voice IC, BLE Bluetooth IC, dual-mode Bluetooth module, wifi module. We have hardware design and software development capabilities. Covering circuit design, PCB design, single-chip microcomputer development, software custom development, APP custom development, WeChat official account development, voice recognition technology, Bluetooth development, wifi technology, etc. It can also undertake the research and development of smart electronic products, the design of household appliances, the development of beauty equipment, the development of Internet of Things applications, the design of smart home solutions, the development of TWS earphones, the development of Bluetooth earphone speakers, the development of children's toys, and the research and development of electronic education products.
06-16

2023

Car Bluetooth Technology Application

Bluetooth (Bluetooth) technology is actually a short-range wireless communication technology. Originally created by telecommunications giant Ericsson as an alternative to RS232 data lines. The use of "Bluetooth" technology can effectively simplify the communication between mobile terminal devices such as handheld computers, notebook computers and mobile phones, and can also successfully simplify the communication between these devices and the Internet, making the data transmission between these modern communication devices and the Internet become faster and more efficient. With the continuous development of technology, the performance stability and security of Bluetooth have also been greatly improved, and users can have a better experience. As the car is an important means of transportation for people, combining Bluetooth technology with the car system will bring great convenience to car production and car service. At present, Bluetooth technology has been widely used in vehicle application systems and network control and other fields, and it will be more widely and deeply used in the automotive field in the future.1. Application status of Bluetooth technology in automobilesThe wide application of Bluetooth technology in the field of automobiles stems from its own high-end technology, especially in the six fields of automobile hands-free communication, rearview mirror, Bluetooth entertainment system, Bluetooth self-diagnosis technology, Bluetooth anti-theft system and car steering wheel control system. aspect.(1) Bluetooth hands-free communication: Nowadays, many cars are equipped with car phones, mainly using the wireless communication technology function of Bluetooth. The car phone can automatically identify the user's mobile phone card, and make a detailed classification of the specific information in it, such as the user's address book, the ownership of the phone, and the phone's own number, and can automatically connect to the car network. These functions can make the user's mobile phone and the car phone communicate with each other in a wireless communication mode. When the user needs to answer or make a call during driving, he can directly use the car phone to communicate, which is also of great significance to the safety of driving.(2) Bluetooth rearview mirror: The Bluetooth rearview mirror of a car is similar to a new type of car phone display. It connects the rearview mirror of the car with the mobile phone through the wireless Bluetooth function, which makes it a cutting-edge vehicle communication device. At this time, the rearview mirror can display the incoming call number when answering the call, and automatically generate the hands-free function. The rearview mirror has a built-in battery that is powered by the car. This application increases the convenience of the user in the driving process, and the mobile phone number of the incoming call can be directly seen without using the mobile phone screen.(3) Car Bluetooth entertainment system: Nowadays, people have higher and higher demands on car performance, and hope to have multiple experiences during driving. Drivers often feel bored during car driving, and the Bluetooth entertainment system can play and display audio, video, etc. in the car through a wireless Bluetooth connection with the user's mobile phone. The car Bluetooth entertainment system is the most widely used navigation all-in-one machine, which adds the Bluetooth car function to the car's navigation device, so that the device not only has communication functions, but also makes it a reality to connect with smart phones. Greatly increase the entertainment of the driving process.(4) Vehicle-mounted Bluetooth self-diagnosis technology: Long-term driving will cause certain faults in the car, and some hidden faults cannot be discovered by the naked eye in time, which will bring great safety hazards to users. The Bluetooth self-diagnosis technology on the car can be sent to the user's mobile phone through wireless Bluetooth transmission, so that the driver can intuitively understand the performance of the car and the reasons for possible failures. Through a new type of data expression, a preliminary assessment is automatically made for the car to ensure the safety factor of driving. At the same time, the detection data of the Bluetooth self-diagnosis technology can also be sent to a professional car maintenance company through the user's mobile phone, and the professional maintenance technicians will conduct a comprehensive evaluation to eliminate possible safety hazards, so that some novice drivers can rest assured Travel by car.(5) Car Bluetooth anti-theft system: How to effectively prevent theft while increasing the convenience of using the anti-theft system when parking has become the focus of the current automotive field. The Bluetooth anti-theft system used today is mainly to wirelessly connect the mobile phone to the Bluetooth of the car, and then use special software to lock and unlock the car door. The anti-theft of the engine is mainly realized by the on-off control of the engine starting circuit by the on-board Bluetooth. The engine can start normally only when the car Bluetooth can be connected to the previously matched mobile phone Bluetooth. Once the Bluetooth of the mobile phone exceeds the connection range of the Bluetooth of the car, the engine of the car will be in a state of being unable to start. For the anti-theft of the car door and engine, two Bluetooth anti-theft systems are used, and these two systems can use two different authentication passwords to increase the safety factor of use.(6) Automobile steering wheel control system: With the continuous rapid development of science and technology, the automobile steering wheel is also developing in the direction of intelligence. More and more automobile steering wheels also realize the control of related operations of the automobile steering wheel panel through Bluetooth data transmission . The cost of this automobile steering wheel control system is relatively low, and at the same time, it has good stability and high safety factor.2. The development trend of Bluetooth technology in automobilesToday, Bluetooth technology has been widely used in people's lives, and its application in automobiles is a powerful proof. It makes car driving more and more convenient, intelligent and humanized, becoming an irresistible social trend in the future. At the same time, in the future development of the automotive industry, Bluetooth technology should give full play to its own special advantages to improve its application level and high-quality data transmission. Next, the wheel force transmission system and the vehicle operating condition recording system are mainly summarized.(1) Wheel force transmission system: The wheel force transmission system requires high-precision standards, and Bluetooth wireless technology can improve the accuracy of data collected by the wheel force sensor during data transmission. The force of the car during driving is multi-directional and multi-dimensional. How to collect these forces well is of great significance to the performance evaluation of the vehicle. In this way, professional evaluation personnel can understand the performance coefficient of various aspects of the vehicle during dynamic driving.(2) Vehicle operating condition recording system: The operating condition of the vehicle is a powerful data for the safety of the vehicle as a whole. Bluetooth technology can effectively obtain accurate data through the acquisition equipment in the car device. Among them, the data transceiver chip has many advantages such as easy installation and carrying, and high accuracy of data transmission at the same time. The data collected wirelessly by Bluetooth technology is more convenient for centralized processing and control.3. Problems and Countermeasures of Bluetooth TechnologyAlthough bluetooth technology can bring great convenience in the driving process, it also has many problems that people still need to solve. Bluetooth technology is everywhere in our life, but many people still have a little understanding of Bluetooth technology, lack of security knowledge related to Bluetooth technology, resulting in a series of problems. The two relatively serious problems of Bluetooth hijacking and Bluetooth eavesdropping are mainly described below.Bluetooth hijacking means that users send business card information anonymously through Bluetooth-related technologies. This approach will not cause mobile phones and other devices to delete or directly change related information, but it may transmit some important private data through Bluetooth, or import some useless spam information from the outside world to mobile phones and other devices . Bluetooth eavesdropping refers to a method where the outside world directly accesses the mobile phone without reminding the device user, so that outsiders can directly obtain important private data through the mobile phone, and even modify relevant information through Bluetooth technology. The well-known Bluetooth eavesdropping technology is to monitor private calls, which will bring great security and privacy problems to users.The main measures taken for these two problems: the manufacturers of related equipment should strengthen the safety factors in all aspects through hardware. At the same time, professional software companies also need to develop and upgrade specific security software to reduce this major hidden danger from a technical perspective. Users should also pay attention to safety issues during operation. For example, when not using Bluetooth technology in daily life, or in some unknown places that are not sure whether it is safe or not, you can set mobile phones and other devices to non-discoverable mode, or set them not to communicate with Bluetooth technology. Unknown device pairing mode.epilogueAt present, Bluetooth technology is still in the development stage, and it also has many problems while bringing convenience to people's life. Widely used in automobiles, when Bluetooth technology brings convenient applications such as hands-free communication and Bluetooth rearview mirrors to users, it also brings certain privacy and security issues. Nowadays, the price of domestic Bluetooth chips is relatively high, and production is more difficult. But with the development of national high-tech, bluetooth technology will definitely bring new changes.The above are the details of the application of Bluetooth technology in automobiles introduced by Shenzhen Zuchuang Microelectronics Co., Ltd. for you. If you have Bluetooth product design and development needs, you can trust us. We have rich experience in custom development of smart electronic products. We can evaluate the development cycle and IC price as soon as possible, and can also calculate the PCBA quotation. We are a number of chip agents at home and abroad: Songhan, Yingguang, Jieli, Ankai, Quanzhi, realtek, with MCU, voice IC, BLE Bluetooth IC, dual-mode Bluetooth module, wifi module. We have hardware design and software development capabilities. Covering circuit design, PCB design, single-chip microcomputer development, software custom development, APP custom development, WeChat official account development, voice recognition technology, Bluetooth development, wifi technology, etc. It can also undertake the research and development of smart electronic products, the design of household appliances, the development of beauty equipment, the development of Internet of Things applications, the design of smart home solutions, the development of TWS earphones, the development of Bluetooth earphone speakers, the development of children's toys, and the research and development of electronic education products.
06-15

2023

Bluetooth dynamic multi-protocol technology

ZigBee Bluetooth dynamic multi-protocol technology1. Introduction to dynamic multi-protocol technologyZigBee/Bluetooth dynamic multi-protocol technology is a technology proposed by Silicon Labs that can run two different protocols of low-power Bluetooth and ZigBee concurrently on a single system chip. This technology combines the main advantages of the two protocols, can complete the main functions of the two protocol stacks, and does not increase the structural complexity and cost of the hardware. Compared with the dual-chip structure with the same function, the dynamic multi-protocol reduces the chip area and cost by nearly 40% by sharing the radio frequency module. In a chip that supports dynamic multi-protocol technology, the software system kernel running in it runs ZigBee tasks and Bluetooth tasks in time based on priority, and quickly modifies the configuration parameters of the radio frequency module when switching tasks, so as to reliably support different protocol stacks. The system also listens to all system-related tasks and inter-task communications while running each task. Therefore, an efficient dynamic multiprotocol system requires a radio scheduler capable of supporting task switching, resource sharing, and managing time slicing, in addition to having a common code infrastructure, sufficient memory, and a common radio interface.2. The principle of dynamic multi-protocol technology2.1 Dynamic multi-protocol system framework(1) Hardware architecture: The hardware framework of the dynamic multi-protocol system is shown in Figure 3-10. RAIL (Radio Abstraction Interface Layer, wireless abstraction interface layer) provides an intuitive and easy-to-configure radio interface and application programming interface (API) to support Various wireless protocols.RAIL includes a public radio configuration interface and radio scheduler, supporting dynamic multi-protocol operation. The radio scheduler assigns default priorities to the different radio operations in each protocol based on importance and time sensitivity to make decisions when radio usage conflicts. The difference in the characteristics of the two protocols can be utilized in dynamic multi-protocol design. The radio usage schedule in the Bluetooth Low Energy mission is very strict and predictable, with both advertisements and connections occurring at predetermined times. In contrast, ZigBee tasks are more flexible in the timing of processing message events, and CSMA-CA in ZigBee has a random dodging mechanism that can delay ZigBee events for several milliseconds. The data packets of Bluetooth beacons are very short, no more than 30 bytes, and only take up about 1ms of radio time when sending. The time between beacons is typically no shorter than 100ms, so Bluetooth only has about a 1% duty cycle in radio use, which means the radio can be used for the main ZigBee network the other 99% of the time. Therefore, it can be ensured that ZigBee can be used to reliably send and receive data while using Bluetooth low energy normally.(2) Software architecture: As shown in Figure 3-11, in the dynamic multi-protocol system, each stack uses the Micrium OS kernel to run a separate RTOS task to provide task switching, and the tasks are equivalent to threads in other operating systems. These tasks use inter-process communication (IPC) mechanisms such as message queues and semaphores to coordinate mutual communication and realize data sharing.2.2 Dynamic Multiprotocol Radio SchedulingSince two different protocols cannot rely on a single radio transceiver to send and receive data at the same time, in order to achieve dual protocols, the two protocols can only share the use of radio transceivers. In order not to impact the functionality of either protocol, they must be able to take the radio out of use intermittently without significant performance degradation or loss of data. In different cases, the different radio operations in the two protocols are not as important or time-sensitive, which requires the use of radio scheduling to plan radio usage.The radio scheduler is a software program that intelligently responds to stack requests to perform radio operations, maximizing reliability and minimizing latency. Each event is broken down into radio operations in the scheduler, corresponding to the radio configuration and priority. If the scheduler receives a higher-priority operation that conflicts in time, it will interrupt the current operation and execute the higher-priority operation, and lower-priority operations that cannot run according to the schedule will fail and be retried by the stack. Once the scheduler starts performing a radio operation, the stack can continue to use the radio until the operation completes or the scheduler receives a higher priority radio operation. BLE radio operations will almost always have higher priority than ZigBee radio operations.Each stack can request the radio scheduler to perform three radio operations: (1) background receive: receive data continuously unless interrupted by other tasks; (2) timed receive: receive data at a future point in time with the shortest possible time; ( 3) Timing sending: send data in the shortest time at a certain point in the future.Each operation has a start time, reserve time, processing time, and priority. Among them, the start time indicates when the radio operation will take place, the reserved time indicates the time when the operation uses the radio and can be accepted by the stack, and the processing time indicates the approximate time required to complete the operation. A send operation usually has a definite processing time, while a receive operation usually has an unknown processing time, which is used by the radio scheduler to determine whether to allow the operation.3. Advantages of dynamic multi-protocol technologyDynamic multi-protocol technology switches and runs different protocols through time multiplexing, and the way of sharing radio transceivers simplifies system design and reduces material costs. By combining the two protocols, Dynamic Multi-Protocol has the key advantages of ZigBee and Bluetooth.Compared with ZigBee technology, dynamic multi-protocol technology has the following advantages: (1) supports direct configuration and control based on smartphones; (2) provides diagnostic functions, and can check the health status of devices through smartphones; (3) can pass Bluetooth performs high-speed OTA upgrade of firmware; (4) supports positioning function.Compared with Bluetooth technology, dynamic multi-protocol technology has the following advantages: (1) ZigBee-side networking is more flexible and simple; (2) ZigBee mesh network with routing method has larger capacity, while BLE Mesh adopts large data flow Flooding, greater network load and poorer scalability; (3) ZigBee devices that comply with the specification have excellent interoperability, while Bluetooth interoperability requires manual modification of the Bluetooth connection settings.Compared with the traditional dual-chip supported dual-protocol (such as ZigBee/Bluetooth gateway), dynamic multi-protocol has the following advantages: (1) By sharing the RF module, the size and material cost are reduced by nearly 40% and the wireless subsystem design is simplified; (2) Dynamic multi-protocol uses time-division multiplexing to reduce signal interference between Bluetooth and ZigBee working in the same frequency band. To sum up, it can be seen that dynamic multi-protocol has obvious advantages over single protocol and dual-chip supported dual-protocol. It not only makes full use of the respective strengths of Bluetooth and ZigBee, but also saves costs and enhances scalability. Therefore, this paper uses dynamic multi-protocol technology at the control center, and uses ZigBee technology as the main communication method between system nodes.This article discusses ZigBee/Bluetooth dynamic multi-protocol technology, explains its working principle, and analyzes the advantages of dynamic multi-protocol technology compared to single protocol and traditional dual-chip dual-protocol.
06-14

2023

Design of Temperature and Humidity Acquisition System

Design and Analysis of Wireless Temperature and Humidity Acquisition System Based on BluetoothAt present, in the existing temperature and humidity data acquisition system, the temperature and humidity data collected by the sensor are transmitted to the host computer through a wired serial port (RS-232 or RS-485) with strong anti-interference ability and mature technology. If there are many collection points, a large number of data lines are required for wired connection between the sensor and the host computer. This way of wired connection will cause great inconvenience; if it is necessary to establish temporary temperature and humidity data collection, use traditional The wired connection method will increase the cost; at the same time, the wired connection method will cause great inconvenience to the construction in harsh environments. Therefore, a low-cost, high-stability wireless data transmission method is required to replace the existing wired data transmission method.Wireless communication communicates by radiating and receiving electromagnetic waves in an open space. On the one hand, it is more seriously affected by various interference and noise in nature than wired; on the other hand, wireless communication signals within a certain area will also interfere with each other. In order to overcome the interference between wireless communication signals, the available wireless channel must be divided into several independent sub-channels and assigned to each user respectively. Although compared with wired communication, wireless communication has great deficiencies in terms of transmission quality and transmission rate, but wireless communication has the advantages of being free from connection constraints, fast and flexible networking, etc., especially providing mobile communication, making wireless communication technology Become the most active field of communication technology research.As a low-cost, low-power, short-range wireless communication technology, Bluetooth is widely used in communication between fixed equipment and mobile equipment.Bluetooth data transmission rate can be as high as 1Mb/s, using frequency hopping/time division multiplexing technology, with one-to-one and one-to-many communication methods. Therefore, this paper proposes a bluetooth-based wireless temperature and humidity acquisition system design and analysis scheme.1. Structural Design of Temperature and Humidity Acquisition SystemData acquisition is an indispensable and important part of industrial systems and the fundamental basis for industrial control. With the development of science and technology, large-scale integrated circuits, single-chip microcomputers, computers, etc. are widely used in the field of industrial control, making digital data acquisition inevitable in the field of industrial control. This design consists of the data acquisition and data transmission part of the lower computer and the data reception and data processing part of the upper computer. Figure 1 shows the system structure diagram. The lower computer is mainly composed of a single-chip microcomputer and a Bluetooth module, and the data acquisition is mainly a DHT11 temperature and humidity sensor; the data transmission part mainly performs wireless data transmission through the Bluetooth module, and transmits the data to the upper computer through the Bluetooth module, and is processed by the upper computer. 2. Hardware design of temperature and humidity acquisition systemIn this design, Arduino single-chip microcomputer is used as the main control single-chip microcomputer of the lower computer. The hardware design of the system is mainly divided into three parts: Arduino microcontroller control part, DHT11 temperature and humidity sensor, Bluetooth wireless communication module. Arduino MCU has rich interfaces, including digital I/O port and analog I/O port, and it supports SPI, IIC, UART and other communication methods. Various types of sensors can be connected externally to control various devices such as lights and motors. Arduino single-chip microcomputer has no complicated underlying code compared with ordinary single-chip microcomputers, and has rich library functions. Different functions can be realized by calling different library functions, and it has the characteristics of convenient programming. Moreover, it has a special set programming download environment IDE, which facilitates the secondary development of Arduino single-chip microcomputer by developers.2.1 DHT11 sensorThe temperature and humidity are measured by DHT11 temperature and humidity sensor. The measured temperature accuracy reaches ±5%RH, the temperature is ±2°C, the measured humidity range is 20-90%RH, and the temperature range is 0～+50°C. DHT11 temperature and humidity sensor is a composite sensor with digital signal output. The DHT11 temperature and humidity sensor contains a resistive humidity sensing element and an NTC temperature measuring element, and is connected with a high-performance 8-bit microcontroller. At the same time, the sensor has a single-wire serial interface, and the temperature and humidity information collected by the sensor can be transmitted to the Arduino microcontroller through the single-wire serial interface.Since the data transmission between the DHT11 sensor and the Arduino microcontroller is through the single-line serial interface, in order to ensure the integrity of the data, the communication time is set at about 4ms, and the data is divided into two parts: a fractional part and an integer part. A complete data transmission It is 40bit, high bit first out.Data format: 8bit humidity integer data + 8bit humidity decimal data + 8bit temperature integer data + 8bit temperature decimal data + 8bit checksum data When the data transmission is correct, the checksum data is equal to "8bit humidity integer data + 8bit humidity decimal data + 8bit temperature integer data + 8bit temperature decimal data" The last 8 digits of the result. When the Arduino microcontroller sends a start signal to the DHT11 sensor, the sensor immediately changes from the low-power standby mode to the working mode, and the DHT11 sensor sends a response signal to the microcontroller, sending out 40bit temperature and humidity data.2.2 Bluetooth communication moduleThis design application is the HC-05 bluetooth module that adopts BlueCore4-Ext chip of British CSR Company. The module supports UART, USB, SPI, PCM, SPDIF and other interfaces, and supports SPP Bluetooth serial port protocol. It has the function of master-slave integration, built-in PCB RF antenna, and can connect 7 slave devices. At the same time, the working voltage of the module is 3. 3-6V, so this module has the advantages of low cost, small size, low power consumption, and high sensitivity of sending and receiving.Because the HC-05 Bluetooth module has two working modes: command response working mode and automatic connection working mode. In the automatic connection working mode, the module can be divided into three working roles: Master, Slave and Loopback. When the module is in the automatic connection working mode, it will automatically transmit the data connected according to the preset method; when the module is in the command response working mode, it can execute AT operation commands, and can send AT commands to the module through the computer to set the control for the module. parameters or issue control commands. The conversion of the working state of the module can be realized by controlling the input level of the external pin of the module.3. Software Design of Temperature and Humidity Acquisition SystemIn order to ensure the readability and succinctness of the program, the Arduino single-chip programming adopts C language for programming. The Arduino microcontroller adopts a timing method for data reception, that is, it sends sampling signals to the DHT11 temperature and humidity sensor every 1 second, and at the same time, the DHT11 transmits the collected data to the microcontroller through the single-line serial port interface, and then stores the data in the internal memory of the microcontroller. Wait for the Bluetooth module to send wirelessly.The Bluetooth module connected to the Arduino microcontroller takes out the data in the internal memory of the microcontroller through the serial port, and then sends the temperature and humidity data to the host computer according to the set communication method.3.1 PC software designThe upper computer system is written in C# language, which is widely used in graphic programming. C# is a safe, stable and simple programming language. It is an object-oriented programming language derived from C and C++. It inherits the functionality of C and C++ while stripping away their complexity. At the same time, the C# programming language combines the visual graphical interface of the VB programming language and the high operating efficiency of the C++ language. First, the system initializes, establishes a Bluetooth connection, and re-establishes the connection if the connection fails. After the connection is successful, data reception starts. If the data cannot be received or the data reception fails, the data reception will be restarted until the data can be successfully received.Since the information transmitted to the upper computer through the Bluetooth wireless module is for data communication with the serial port, the receiving serial port number, baud rate, parity bit, data bit and stop bit must be set in the upper computer. Click to start receiving and the system will automatically receive information every 5 seconds. If manual collection is required, you can directly click manual collection to switch between automatic and manual. The collected information will be displayed in the right box, and the formats are time, temperature, and humidity.If you need to save the collected data for later analysis and sorting, you can click Save Data, and the system will automatically save the data as a file in TXT format.SummarizeThis paper mainly designs and implements a Bluetooth-based wireless temperature and humidity acquisition system. Through Bluetooth wireless communication, the collected data is sent to the host computer acquisition system, and the acquisition system is responsible for receiving, processing, information extraction and storage of data. Considering the characteristics of communication in practical applications, the communication method in this paper adopts the combination of Bluetooth wireless communication and serial port communication. The establishment and implementation of bluetooth communication and the implementation of serial communication are briefly introduced respectively. The upper computer software design adopts C# language for programming to realize the system initialization, establish bluetooth communication, data receiving and other process management. The experimental results show that the hardware design of the system is reliable and practical, and the software design is simple and convenient for secondary development, which can meet the data acquisition and communication requirements in different situations.The above is the design and analysis of the Bluetooth-based wireless temperature and humidity acquisition system introduced by Shenzhen Zuchuang Microelectronics Co., Ltd. If you have Bluetooth product design and development needs, you can trust us. We have rich experience in custom development of smart electronic products. We can evaluate the development cycle and IC price as soon as possible, and can also calculate the PCBA quotation. We are a number of chip agents at home and abroad: Songhan, Yingguang, Jieli, Ankai, Quanzhi, realtek, with MCU, voice IC, BLE Bluetooth IC, dual-mode Bluetooth module, wifi module. We have hardware design and software development capabilities. Covering circuit design, PCB design, single-chip microcomputer development, software custom development, APP custom development, WeChat official account development, voice recognition technology, Bluetooth development, wifi technology, etc. It can also undertake the research and development of smart electronic products, the design of household appliances, the development of beauty equipment, the development of Internet of Things applications, the design of smart home solutions, the development of TWS earphones, the development of Bluetooth earphone speakers, the development of children's toys, and the research and development of electronic education products.
06-13

2023

Appliance network remote control

Application of bluetooth technology in constructing centralized remote control of electric appliance networkThe electrical network is to use digital, network, and intelligent control technologies to manage and control existing ordinary electrical appliances, making them networked, intelligent, and able to realize remote control and management. To realize the networking of ordinary electrical appliances, the first thing to solve Interconnection problems, and the uniqueness (that is, accurate identification) of the electrical appliances in the network. At the same time, communication problems between electrical equipment should also be solved in order to realize electrical interconnection and remote control.To achieve remote control, two major problems must be solved: equipment networking and remote mutual control using the existing public network. As far as the current indoor networking connection methods are concerned, there are the following networking forms:(1) Wired networking mode. That is, the use of network communication physical lines to connect electrical appliances to realize the interconnection of devices and achieve the purpose of networking. This wired connection has strong ability to resist network interference, but the network is in the indoor networking process. There are many disadvantages in the network: such as how to wire indoors, solve the problem of wiring spider webs, how to add control points in the established network, how to move the access point after the equipment is moved, etc. Obviously, the flexibility of the wired network is too poor , users cannot add devices and mobile devices at will, and cannot realize "plug and play" of devices. At the same time, the reliability of network connection points is poor, and there are often communication connection plugs in wired connections, which are more prone to abnormal network device connections, resulting in Dropouts, i.e. there is a problem with "connection reliability".(2) Infrared networking mode. This kind of networking has strong flexibility and can realize "plug and play", and the connection reliability is also strong. The complex space cannot be used, and there is a problem of "space limitation".(3) Microwave networking method. This networking method has a long transmission distance and is suitable for complex terrain, open and unobstructed, and transmission and connection between two points that can see each other; disadvantages: high cost, once blocked, communication will not be possible .(4) Wireless networking connection method. This connection method can overcome the shortcomings of insufficient wired networking methods. For users, the equipment has strong flexibility in network access, and the networking of equipment is also convenient and reliable, and there is no problem of space obstruction. At the same time, users can also move and add devices more freely, which can realize "plug and play".Therefore, wireless networking is the first choice in the process of building a home appliance network. However, as far as the current wireless networking technology is concerned, it faces the following problems:(1) How to realize the interconnection and control information exchange between electrical appliances, control centers and public networks. (2) Since there may be overlapping coverage areas of wireless networks, it is necessary to solve how to accurately identify which electrical equipment belongs to the network equipment and which electrical appliances The equipment belongs to the problem of equipment outside the network. (3) How to solve the problem of extending the network outward and realizing remote control.As far as conventional wireless technology is concerned, it is relatively difficult to solve the problems in the above networking process, especially the identification process of devices in the network, and to determine whether the electrical device has completed receiving the control command and entered the work during the control process. State. To solve the above identification and judgment process, modern wireless communication technology must be adopted to realize the mutual communication, identification and control process between the control center and electrical equipment. In the current wireless communication technology, the low-cost Bluetooth technology is the first choice .1. Features of Bluetooth technology system1.1 Introduction to Bluetooth Technology"Bluetooth" (Bluetooth) was originally the name of the king who unified Denmark in the tenth century. A small-scale wireless network technology, when Bluetooth was launched, it aimed at wireless local area network communication. Bluetooth is an open standard for low-cost short-range wireless data and voice transmission. It can connect various digital system equipment (including communications, computer terminals, etc.) equipment, etc.) adopt wireless networking. It adopts 2.4GHz ISM frequency band and frequency modulation and frequency hopping technology, 79 1MHz bandwidth frequency hopping points, 1600 hops/S, supports 64kb/s real-time voice transmission and data transmission, and the transmission power is respectively 1mW, 2.5mW and 100mW have low power consumption and little harm to the human body. The radius of the effective transmission range is 10cm to 10m. If some peripherals are added to increase the power, the transmission distance can reach a radius of 100m. Use a globally unified 48-bit device identification code .Data connection methods are connection-oriented service SCO and connectionless service ACL. Working modes are PARK (sleep), HOLD (hold), and SNIFF (breathing).1.2 System structureThe system structure of Bluetooth technology is divided into three parts: the underlying hardware module, the intermediate protocol layer and the high-level application. The underlying hardware part includes wireless frequency hopping (RF), baseband (BB) and link management (LM). The wireless frequency hopping layer passes The 2.4GHz unlicensed ISM frequency band microwave realizes the filtering and transmission of data bit streams. This layer protocol mainly defines the conditions that the Bluetooth transceiver needs to meet to work normally in this frequency band. The baseband is responsible for frequency hopping and Bluetooth data and information frames. Transmission. Link management is responsible for connecting, establishing and tearing down links and performing security control.1.3 TopologyThe Piconet (micronet) structure using Bluetooth technology networking is a network composed of multiple devices sharing the same channel. This topology divides the devices into master devices and slave devices. The master device that proposes communication requirements communicates passively The device is called a slave device. A master device can communicate with up to 7 slave devices at the same time, and can connect multiple sleep devices that are synchronized but not communicating. All devices are equal during operation, and there is no master-slave Scatternet (distributed network) of Bluetooth is formed by multiple independent and asynchronous piconets communicating with each other.1.4 Authentication technologyAuthentication technology is an important performance indicator to distinguish between traditional radio frequency technology and Bluetooth technology. The authentication and encryption services for devices are provided by the physical layer. Authentication authentication adopts password-response mode, through personal identification code PIN, 128-bit The random number and the BD_ADDR of the device are generated and a matching 128-bit authentication word is generated. Through authentication, a link word is created for them, and the Bluetooth device can store the link word for future authentication, avoiding entering the PIN code for each authentication .In the connection process, authentication is an extremely important part of any Bluetooth system. It allows users to add their own trusted Bluetooth devices, and through reverse authentication, the establishment of One-to-one correspondence, during data transmission, a dedicated data channel is established through a unique link word for transmission. Other Bluetooth devices with different link words in the network are still in a dormant (PARK) state and do not participate in data transmission and receiving activities. If the user If there is a higher level of confidentiality requirements, an effective transport layer and application layer security mechanism can be used for encrypted transmission. Through the authentication and identification mechanism, the main device in the network can accurately identify a certain device in the network, and establish Link, to accurately communicate and control the device with instructions and data, and return the control status information through the link. This technology solves the problem of mutual identification between devices.With the above series of advantages, the Bluetooth technology can effectively overcome and solve the problems existing in the networking process mentioned above, and select technical means for the best networking.2. Application of Bluetooth technology in network appliancesThrough the four basic access modes of the Bluetooth technical specification, electrical network construction and data exchange can be carried out. Through the Bluetooth Access Application Mode (GAP), the Bluetooth units can discover and establish connections with each other; through the Service Discovery Application Mode (SDAP), the interface of the discovery protocol , to send a "send" or "receive" request signal to other Bluetooth units; through the serial port application pattern (SPP), a virtual serial port is established between two Bluetooth units; through the general object exchange application pattern (GOEP), the data is passed through the virtual The serial port is transmitted to another Bluetooth unit. Using the Bluetooth technical specification, a new centralized remote control mode of the electrical network is realized. It truly realizes "zero wiring, plug and play".In the centralized remote control structure of the entire network system, the network appliance centralized controller is the Bluetooth master device controlled by the core of the entire system, which acts as a bridge. Through the centralized controller keyboard, Internet, telephone and other communication methods, it accepts user operation instructions, And according to the user's work requirements for the designated household appliances in the network, the control command is sent to the designated controlled network through the Bluetooth device in a timely and accurate manner to control its work from the Bluetooth slave device, and the operation control status data of the designated electrical controlled terminal is sent through The bluetooth of the controlled end returns to the centralized controller, and notifies the user of the result through voice and WEB, realizing the centralized control and remote management of network appliances.In the network appliance centralized controller, every time a new legal network appliance is added, Bluetooth authentication is performed, and the link word between the network appliance centralized controller and the appliance is created, confirmed as a legal device in the network, and stored for subsequent use Authentication is used to distinguish critical peripheral non-network electrical equipment to achieve precise control. In the electrical client, a Bluetooth receiving and sending control device is also embedded. The instructions issued by the centralized controller are transmitted to the designated client via the Bluetooth wireless network , and judge and identify the received instructions, and control according to the instruction requirements. At the same time, through the electrical appliance working status detection unit, the real-time working status of the electrical appliances under control is detected, and the detection results are fed back. Through the wireless Bluetooth network, The real-time feedback is transmitted to the centralized controller, and the user is notified of the current working status of the controlled electrical appliances in real time through voice or WEB, thereby completing a complete real-time remote wireless control.SummarizeCompared with the traditional wireless transmission technology, Bluetooth technology has incomparable advantages. This technology solves the long-term broadcast transmission mode of radio frequency wireless technology that can only be one-to-many, and uses authentication technology to realize one-to-one secure authentication transmission. Mode. It is a new type of transmission standard. There are more and more products based on Bluetooth technology. In short, the wide application of Bluetooth technology will bring more convenience to people's life and work.The above are the details of the application of Bluetooth technology in the construction of centralized remote control of electrical appliances network introduced by Shenzhen Zuchuang Microelectronics Co., Ltd. If you have Bluetooth product design and development needs, you can trust us. We have rich experience in custom development of smart electronic products. We can evaluate the development cycle and IC price as soon as possible, and can also calculate the PCBA quotation. We are a number of chip agents at home and abroad: Songhan, Yingguang, Jieli, Ankai, Quanzhi, realtek, with MCU, voice IC, BLE Bluetooth IC, dual-mode Bluetooth module, wifi module. We have hardware design and software development capabilities. Covering circuit design, PCB design, single-chip microcomputer development, software custom development, APP custom development, WeChat official account development, voice recognition technology, Bluetooth development, wifi technology, etc. It can also undertake the research and development of smart electronic products, the design of household appliances, the development of beauty equipment, the development of Internet of Things applications, the design of smart home solutions, the development of TWS earphones, the development of Bluetooth earphone speakers, the development of children's toys, and the research and development of electronic education products.
06-12

2023

Bluetooth sniffing technology solution

In recent years, Bluetooth technology has enjoyed unprecedented popularity and development speed, and its coverage on mobile devices is even more amazing. In fact, Bluetooth has become the primary connection method for wireless accessories and smart devices. Unfortunately, recent research has shown that the two-level stream encryption scheme adopted by Bluetooth has many flaws, and user privacy is potentially compromised. On the other hand, new communication software that uses Bluetooth to transmit information is used in illegal and criminal activities, seriously affecting social harmony and stability. Faced with the development of Bluetooth technology, we should actively take countermeasures and strengthen research in the direction of Bluetooth sniffing.1. Bluetooth sniffing technical background1.1 Bluetooth technologyBluetooth technology is a wireless data exchange method that supports short distances. A Bluetooth network established by a master device and one or more slave devices is called a piconet (Piconet). Bluetooth technology is widely used in short-distance wireless communication because of its low power consumption, low cost and strong flexibility. According to practical needs, the maximum transmission power of Bluetooth devices is also divided into three levels, and its coverage also changes with the power. Currently, the Bluetooth SIG oversees research on the Bluetooth specification, manages the certification program, and maintains trademark rights.1.2 Radio layerThe lowest layer of the Bluetooth protocol stack is called the radio layer. Bluetooth technology adopts the 2.4GHz working frequency band, which is an open and common wireless frequency band (ISMBand) all over the world, without payment and application, which ensures that Bluetooth can obtain a wider range of use. Bluetooth uses frequency hopping technology and performs frequency hopping at a rate of 1600 hops/s. The transmitted data will be divided into multiple data packets, and the data packets will be transmitted separately through the designated 79 Bluetooth channels. Each channel occupies 1MHz. Bluetooth's The actual use band is 2400MHz～2483.5MHz (including the guard band). This approach leads to difficulties in selective interception, since the attacker often needs to know the consecutive hopping sequences.1.3 Baseband layerThe baseband layer is responsible for managing the physical connection and ensuring the physical connection between the units in the piconet composed of Bluetooth devices by radio frequency. Each Bluetooth device has a unique 48-bit Bluetooth device address (BD_ADDR), which is divided into 3 parts, including 24-bit low-end address part (LAP), 8-bit high-end address part (UAP) and 16-bit non- Effective Address Part (NAP). This address can be said to be the computing core of Bluetooth technology, responsible for almost all the control parameters of Bluetooth normal work, such as keys and frequency hopping sequences are calculated from this address.1.4 Packet structureAll Bluetooth data packets are encapsulated according to a unified structure, consisting of access code, header and payload. A valid data packet must contain an access code, which is used for data synchronization and DC offset compensation. A simplest bluetooth data packet, such as an ID packet used for paging, inquiry and corresponding process, can only contain a 68bit access code. There is a very important package in the Bluetooth communication process - the Frequency Hopping Synchronization (FHS) package, which contains the BD_ADDR and clock information of the Bluetooth device.1.5 Connection establishmentFor Bluetooth data transfer, a connection must first be established. First, the master device broadcasts an ID packet as a query. At this time, 32 broadcast channels out of 79 Bluetooth channels are used. After the slave device receives this packet, it will send an FHS packet, which contains the BD_ADDR and clock information of the slave device. The master device that receives the FHS packet enters the paging state, and calculates a specific response time according to the frequency hopping sequence of the slave device, and sends the ID packet. The slave device will scan the external paging at regular intervals, and after receiving the response ID packet from the master device, it will send an ID packet in response to the response. After the master device receives the slave device ID packet, it sends an FHS packet to determine the frequency hopping sequence of the connection. Finally, the master and slave devices respectively send ID packets and FHS packets to verify and establish a connection.In the piconet, all devices share the clock of the master device, with a clock cycle of 312.5 µs, and two cycles constitute a time slot of 625 µs. Normally, the master device transmits data from even-numbered slots, and the slave device transmits data from odd-numbered slots.2. Bluetooth sniffing scheme2.1 Difficulties in Bluetooth sniffingThe first hurdle in Bluetooth sniffing is intercepting the Bluetooth frequency hopping sequence. If you want to obtain a complete Bluetooth data transmission, you need to monitor all 79 Bluetooth channels, and you must intercept and filter to obtain complete data packets, which requires you to know the correct Bluetooth frequency hopping sequence. There are two ways to obtain the Bluetooth frequency hopping sequence, one is to rely on powerful hardware and software equipment, and the other method needs to wait for the device to re-establish the connection, and obtain the frequency hopping sequence from the data packet that establishes the connection.Another problem is that common Bluetooth hardware automatically filters based on the access code of the packet. Since the filtering behavior occurs at the hardware level, it cannot be solved by the design of the upper layer software, and must rely on corresponding hardware devices to solve this problem.2.2 Bluetooth packet capture tool WiresharkWireshark is widely used as a commonly used packet capture tool. The Bluetooth protocol standard has been added to Wireshark above 1.12, which means that the captured Bluetooth data packets can be analyzed through Wireshark, which provides great convenience for sniffing work. At the same time, Wireshark also provides the function of monitoring the Bluetooth interface of the machine, which can monitor the Bluetooth devices connected to the machine. Figure 1 shows the Bluetooth packet information captured by Wireshark. Figure 1 shows some data packets in the process of establishing a connection between the computer and the Bluetooth headset. Number 27 is a data packet broadcast and transmitted by the computer as the master device to inquire about nearby Bluetooth devices. No. 28 to No. 31 are the query responses from the Bluetooth headset to the computer, and the three data packets except No. 28 all contain the BD_ADDR of the headset. Since then, the computer and the Bluetooth headset gradually establish a Bluetooth connection by sending data packets to each other.2.3 Bluetooth wireless development platform UbertoothUbertoothOne is a hardware for Bluetooth research designed and provided by the Ubertooth project team. Ubertooth is an open source 2.4GHz wireless development platform for Bluetooth monitoring. UbertoothOne is also connected to the computer through the USB interface.The real-time Bluetooth spectrum information can be visually observed by using the SpecanUI tool, as shown in Figure 2. In the observation in Figure 2 there is a Bluetooth headset connected to the mobile phone.It can be found that active wireless signals are mainly concentrated between 2403Hz and 2446Hz, which means that the data transmission between the mobile phone and Bluetooth is mainly concentrated on these channels. In addition, 2402Hz, 2426Hz, and 2480Hz are fixed broadcast channels, which are used to send broadcast data between unconnected devices, establish connections and discover remote devices. These 3 channels also have obvious characteristics in the frequency spectrum.UbertoothOne can also support functions such as selecting the channel to monitor, or capturing Bluetooth data packets. The captured Bluetooth packets can be analyzed by software such as Wireshark. Sending Bluetooth data packets through UbertoothOne is currently not possible, which means that UbertoothOne cannot be used to inject Bluetooth data packets.in conclusionThere are still many difficulties in the realization of the Bluetooth sniffing scheme. On the other hand, the high threshold also put an end to the attempts of a large number of criminals to use Bluetooth to steal citizen information. However, software that communicates via Bluetooth, such as FireChat, is often used in illegal and criminal activities, which has seriously endangered public safety. In-depth research on Bluetooth technology and active research on Bluetooth sniffing solutions can not only solve current problems, but also prepare for future Bluetooth security issues.The above is the Bluetooth sniffing solution technology introduced by Shenzhen Zuchuang Microelectronics Co., Ltd. for you. If you have Bluetooth product design and development needs, you can trust us. We have rich experience in custom development of smart electronic products. We can evaluate the development cycle and IC price as soon as possible, and can also calculate the PCBA quotation. We are a number of chip agents at home and abroad: Songhan, Yingguang, Jieli, Ankai, Quanzhi, realtek, with MCU, voice IC, BLE Bluetooth IC, dual-mode Bluetooth module, wifi module. We have hardware design and software development capabilities. Covering circuit design, PCB design, single-chip microcomputer development, software custom development, APP custom development, WeChat official account development, voice recognition technology, Bluetooth development, wifi technology, etc. It can also undertake the research and development of smart electronic products, the design of household appliances, the development of beauty equipment, the development of Internet of Things applications, the design of smart home solutions, the development of TWS earphones, the development of Bluetooth earphone speakers, the development of children's toys, and the research and development of electronic education products.
06-11

2023

Environmental data detection car

Design of bluetooth control car based on Arduino environmental data detectionWith the development of science and the continuous improvement of social productivity, the content of environmental monitoring has gradually developed from the monitoring of industrial pollution sources to the monitoring of the environment. Environmental monitoring has been paid more and more attention by people, but the addition of new technologies and methods is still in the research and development stage, mainly using manual and semi-automatic methods to collect environmental factors, with low efficiency and poor accuracy. Establishing a fast, simple and accurate environmental detection method is conducive to the realization of environmental supervision and control. Arduino is an open-source electronic design platform for single-chip microcomputers. There are many interfaces designed for sensor modules on its hardware development board. Just plug in the corresponding packaged modules, and it can read the signals obtained by the sensor from the outside world and program them. Under the command of the corresponding feedback, improve the efficiency of the program. The paper proposes an Arduino-based environmental data detection bluetooth control car design, which controls the left and right, forward and backward movements of the car through the bluetooth of the mobile phone, transmits the environmental data collected by the sensor on the car in real time, and triggers an alarm when the concentration value exceeds the threshold device.1. Design of environmental data monitoring car systemThe system uses the Arduino single-chip microcomputer as the core control board, and simultaneously completes the control of the car status and the sending, receiving and display of environmental data through the Bluetooth of the mobile phone.In the figure, the power supply part is composed of a lithium battery pack and a linear DC regulated power supply to provide a stable driving current for the driving motor of the trolley system; There is a DC motor to control the left and right rotation, forward, backward and stop of the car; the temperature and humidity sensor and the combustible gas sensor are connected to the Arduino main control for the collection of environmental data. The Bluetooth module realizes the communication between the car and the mobile phone, so that the car can receive the instructions sent by the mobile phone and transmit the collected data back to the mobile phone, and control the movement of the car through the mobile phone.2. Bluetooth smart car hardware designThe hardware part mainly includes Arduino development board, HC-05 Bluetooth module, DHT11 temperature and humidity sensor, MQ-2 smoke and gas sensor module, L298N motor drive module, DC gear motor, etc. Among them, the Arduino development board is the control center of the car system, and the Bluetooth module is the communication module between the mobile phone and the car. The motor drive module drives the forward and reverse rotation of the DC deceleration motor to control and change the motion state of the car. The DHT11 temperature and humidity sensor and the MQ-2 smoke and gas sensor are used as the environmental data acquisition module to detect the temperature, humidity, smoke or combustible gas concentration. .In this design, pin 0 (RX) and pin 1 (TX) of the Arduino control board are respectively connected to the TX and RX pins of the Bluetooth module; the IN1, IN2, IN3, IN4 interfaces of the L298N motor drive module are connected to the The modulated pins 6, 9, 10, and 11 are connected; the temperature and humidity module is connected to the digital pin 5; the smoke and gas sensor needs to be connected to the analog serial port, so connect it to the A0 port, and the beeper associated with its function The buzzer is connected to pin 2. After the pin allocation of the Arduino development board is completed, connect the OUT1 and OUT2 output ports of the L298N motor driver module to the left DC geared motor, and connect the other side to the right DC geared motor in the same way.2.1 Arduino main controller unitThe Arduino controller mainly includes single-chip microcomputer, digital serial port, analog serial port, crystal oscillator and 5V voltage regulator and other components (as shown in Figure 3). The development board is connected to the computer through the USB data interface to compile and import the program. After writing the program code in the IDE, the program is uploaded to the Arduino development board through the USB interface, and the single-chip microcomputer on the development board performs program execution and data processing. Pins 3, 5, 6, 9, 10 and 11 of the Arduino UNO development board designed in this design have pulse width modulation (PWM) function, which can provide the function of speed regulation of steering gear, motor drive module and other components.2.2 Data Acquisition UnitThe environmental data acquisition function mainly relies on the digital temperature and humidity sensor and MQ-2 smoke and gas sensor to realize the detection of temperature and humidity and the concentration of smoke or combustible gas.(1) DHT11 temperature and humidity sensor: DHT11 digital temperature and humidity sensor mainly includes acquisition technology and sensing technology. The sensor includes wet resistance and NTC resistance. Its internal schematic diagram is shown in Figure 4. Wet resistance is to cover a layer of film on the substrate, the film is made of moisture-sensitive material. When the moisture-sensitive film is in contact with water vapor in the air, the resistance value of the element will change with the change of hydrogen ion concentration in the process of moisture absorption and dehumidification, and the built-in conversion circuit will calculate the final voltage change and compare it with the change of humidity. Corresponding, so that the humidity in the environment can be measured. NTC resistance, that is, negative temperature coefficient resistance, means that when the ambient temperature rises, the resistance value decreases, and the voltage output will also increase accordingly, and the conversion circuit makes the voltage value correspond to the ambient temperature according to the corresponding change.(2) MQ-2 smoke gas sensor: The gas sensitive resistor is the core component of the MQ-2 smoke gas sensor to measure the concentration of combustible gas. It converts the detected combustible gas concentration into a voltage and uploads it to the microcontroller. There are two types of gas sensitive resistors, P-type semiconductors and N-type semiconductors. When it is under normal conditions, the gas-sensitive resistor of N-type semiconductor is in the state of anion deficiency. When the gas-sensitive resistor is in contact with flammable gas molecules, electrons will move from flammable gas molecules to N-type semiconductor, semiconductor The resistance value of will also decrease, thus changing the voltage value of the circuit. For the gas-sensitive resistor of the P-type semiconductor, the cation is absent, and the resistance of the semiconductor will increase. Since the temperature has a great influence on the conductivity of the semiconductor, it needs to be heated when the MQ-2 smoke gas sensor is used to measure the concentration of flammable gases.2.3 Communication unitThe mobile phone communicates with the detection car through the Bluetooth module, and sends the detected environmental data back to the Bluetooth serial port assistant APP of the mobile phone through the Bluetooth module, so as to realize the real-time monitoring of the environmental parameters by the mobile phone and the forward, backward and direction control of the car. The HC-05 Bluetooth module is paired with the mobile phone Bluetooth to realize the communication function. The HC-05 Bluetooth module has six pins: VCC, GND, TXD, RXD, KEY, LED. When the Bluetooth module is in different communication states, the pins on the module The indicator light will show different flashing states, which is convenient for users to judge whether the Bluetooth module is working normally. If the KEY is connected to a high level or the Bluetooth module is powered on at the same time, the indicator light will flash slowly once per second, and the module enters the AT state and cannot perform pairing tasks; The frequency flashes twice. When the Bluetooth module is paired successfully, the indicator light will turn into a double flash state, flashing once every two seconds. When the KEY is connected to a high level in the matching state, the module will exit the matching state and enter the AT state, but at this time the flashing frequency of the indicator light is consistent with the state of the indicator light in the matching state.2.4 Bluetooth smart car motion unitThe movement function of the car is mainly realized by the L298N motor drive module and DC3V-6V DC gear motor. L298N (as shown in Figure 5) has two built-in H-bridges to maintain the voltage across the motor between high and low levels. In addition to converting the 12V power supply into 5V power supply to the development board, this module can also drive and control two motors. When the enable terminals ENA and ENB are both high, the different states of the DC geared motor can be controlled by combining different IN1 and IN2 states. state of motion.Before performing pulse width modulation on the DC motor to adjust the motor speed, it is necessary to determine the connection between the IN1 and IN2 ports and the DC motor, and determine the rotation direction of the motor. After determining the direction of rotation of the DC motor, the corresponding relationship between the pins of the microcontroller and the left and right motors is determined through the program. When the speed of the DC geared motor needs to be adjusted, the PWM pulse is output for speed regulation. When the IN1 and IN2 interfaces are both in the 0 state or both in the 1 state, the corresponding DC motor controlled by the two output interfaces brakes.3. Software design of bluetooth environmental data detection carThe software part adopts modular design, which is mainly divided into main program, data acquisition program, Bluetooth communication program, and car motion control program. The program design flow chart is shown in Figure 7. When a certain function program is designed, it will be imported to the Arduino development board , after importing, check whether the function is realized normally. If it can be realized normally, then design the next function program. If the function cannot be realized normally, then re-debugging this part of the program, when the four parts of the function program are completed, then combine the four parts of the function program, continue to import the program and debug, when all the functions are realized, the program design is completed .The mobile phone communicates with the detection car through the Bluetooth module, sends different commands to realize the control of the car, realizes the mobile phone's forward, backward and direction control of the car, and sends the detected environmental data back to the Bluetooth serial port assistant APP of the mobile phone through the Bluetooth module. An alarm is issued when the environmental data exceeds the threshold.SummarizeThis design completes the system design for the bluetooth control car for environmental data collection, communicates with the data collection car through the mobile phone bluetooth, wirelessly controls the movement state of the car, and the bluetooth control range is within 10m, and transmits the data collected by each sensor through the bluetooth module Go back to the bluetooth serial port assistant APP on the mobile phone, and realize the alarm function according to the smoke concentration.The above are the design details of the Arduino-based environmental data detection Bluetooth control car introduced by Shenzhen Zuchuang Microelectronics Co., Ltd. If you have Bluetooth product design and development needs, you can trust us. We have rich experience in custom development of smart electronic products. We can evaluate the development cycle and IC price as soon as possible, and can also calculate the PCBA quotation. We are a number of chip agents at home and abroad: Songhan, Yingguang, Jieli, Ankai, Quanzhi, realtek, with MCU, voice IC, BLE Bluetooth IC, dual-mode Bluetooth module, wifi module. We have hardware design and software development capabilities. Covering circuit design, PCB design, single-chip microcomputer development, software custom development, APP custom development, WeChat official account development, voice recognition technology, Bluetooth development, wifi technology, etc. It can also undertake the research and development of smart electronic products, the design of household appliances, the development of beauty equipment, the development of Internet of Things applications, the design of smart home solutions, the development of TWS earphones, the development of Bluetooth earphone speakers, the development of children's toys, and the research and development of electronic education products.

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