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Voice wireless doorbell solution
In modern homes and offices, wireless doorbells and wireless anti-theft alarms have been widely used, but most of the wireless doorbells on the market are simple, that is, the data transmission between the remote control and the receiver adopts a non-encoded type. The production cost of the wireless doorbell is low, but it has few functions, is inconvenient to use and has poor performance, and often cannot meet people's needs. With the rapid development of microelectronics technology, wireless technology and network technology and the substantial improvement of people's living standards, the demand for more humanized wireless remote control music doorbells with more functions and better performance is increasing.
1. The overall design of the wireless doorbell system
The wireless doorbell system mainly takes the single-chip microcomputer as the control core, uses the wireless communication module as the information transmission channel, and uses the voice chip for voice response. The single-chip microcomputer mainly adopts AVR single-chip microcomputer with anti-interference ability and high cost performance. The outdoor control chip is set as the master controller, and the indoor control chip is set as the slave controller. When the master controller sends a signal request to the slave controller, the master controller will transmit the request information to the master controller by means of wireless communication transmission. The controller; the main controller gives corresponding response information according to the indoor condition and the button press condition. In order to increase the stability of the system and the reliability of information transmission, the wireless communication module and the sensor module mainly adopt integrated digital modules.
This system includes two parts: outdoor master control unit and indoor slave control unit. The outdoor master control unit includes five parts: master controller, doorbell button unit, voice prompt unit, power supply unit and wireless transmission unit; the indoor slave control unit includes: slave controller, buzzer prompt unit, key response unit, human body induction unit , wireless transmission unit, power supply unit six parts. System block diagram shown in Figure 1.
When the master control unit receives a call from the doorbell button, it sends call information to the indoor slave control unit through the wireless transmission unit. , giving different response signals. The response signal is sent to the main control unit through the wireless transmission unit, and the voice prompt unit sends out different prompt sounds to remind visitors. This system adopts wireless transmission, which not only reduces the trouble caused by wire connection, but also does not affect the indoor appearance; uses the human body induction unit to sense whether there are people in the room, and uses the voice prompt circuit to give a response signal to the outside visitor for the situation inside the house, so that the outdoors can accurately It is convenient to know whether there are people in the house and whether the owner is convenient for reception.
2. Hardware design of wireless doorbell system
1. Main control chip selection. The controller of the system adopts Atmega8L microcontroller of AVR series. ATmega8L is a special single-chip microcomputer, which integrates a large-capacity memory and rich and powerful hardware interface circuits inside the chip, and has in-system programmable features. These features make it very cost-effective, and it is more comprehensive and perfect in terms of stability, anti-interference and flexibility.
2. Selection of wireless communication module. Since the distance between the home and the outside of the home or office can reach about 100 meters, and communication needs to penetrate rooms, doors, windows, etc., it requires relatively strong transmission and penetration capabilities, and it is necessary to choose a wireless transmission module with a relatively low operating frequency. . This system uses the nRF905 wireless communication module as the information transmission channel of the wireless doorbell system, and the working voltage is 3.3~3.6 V. Therefore, the 3.3 V output voltage is composed of the HT7533 chip to provide the power supply voltage for the nRF905 module. This module works on 3 ISM channels of 433/868/915 MHz.
3. Choice of voice chip. Using programmable voice recording chip ISD4004. It can send out different designated prompt sounds and music according to different needs, and the sound effect is better and the sound is more pleasing to the ear. The output of the voice chip should be connected to a loudspeaker that can emit sound, but for audio signals, sufficient power is needed to make the sound clearer. Therefore, the output of the voice chip must amplify the power of the signal, using an audio power amplifier The LM386 chip can only be connected to the speaker after the power is amplified and output, so that the sound is clear and full.
4. The design of human detection transmission unit. It adopts infrared diffuse emission photoelectric switch, the model is E18-D80NK, and the working voltage is 5 V DC voltage, which can share a power supply voltage with the microcontroller. This is a photoelectric sensor that integrates emission and reception. The object is not limited to metal, and all objects that can reflect light can be detected. The sensor has the characteristics of long detection distance, little interference by visible light, low price, easy assembly and convenient use.
5. Key response circuit design. The system uses buttons as the response to information requests, and there are three function buttons. The functions are: button S1 is used to prompt the slave to send the language information of "coming soon" to the master, and button S2 is used to prompt "busy, please wait." ", press S3 to prompt the voice message "No one in the house". To sum up: the production of this subject uses the ATmega8L single-chip microcomputer as the control chip, the wireless communication module uses the nRF905 wireless communication module for communication, the sound prompt module uses the ISD4004 voice chip to convey voice information, and the detection device uses infrared diffuse emission sensors. Through these four modules to form a wireless doorbell system based on AVR microcontroller design.
3. Software Design of Wireless Doorbell System
1. Host control program. Detect whether there is a button pressed, if not, wait and continue to detect; if so, call the voice program, set the music through the speaker response for 30 s, and call the wireless transceiver module program, send a request signal to the slave, wait for the slave to respond, If it is detected that the slave machine gives a response signal, it will respond to the corresponding voice prompt through the voice process according to the feedback signal. The host flow chart is shown in 2.
2. Slave control program. The main program idea of the slave: detect whether the host sends a request through the wireless transceiver program, if not, wait and continue to detect; if a request is detected, respond to the buzzer sound to prompt, detect whether the human body infrared sensor signal is low level, if so , scan whether the function button is pressed, judge which function button is pressed according to the high and low level changes of the control port corresponding to the button, and send the corresponding signal to the host through the wireless transceiver program; The host sends a message of "no one in the house". The flow chart of the slave machine is shown in Figure 3.
After power-on initialization, check whether the host sends a request through the wireless transceiver program, if not, wait and continue to detect; if a request is detected, the buzzer will sound to prompt, and check whether the signal of the infrared sensor of the human body is at a high level, if the detection signal is High level, indicating that no human body signal has been detected, continue to detect, and judge whether the time reaches 30 s. When the time reaches 30 s and no human body signal is detected, the wireless transmission unit will send the message "no one in the house" to the host. If it is detected that the human body infrared sensor signal is at a low level, it means that the human body signal is detected, and the program continues to execute downwards. Whether the scanning function button S1 is pressed, if pressed, sends a "coming soon" message to the host through the wireless transmission unit; if If it is not pressed, whether the continue scanning function button S2 is pressed, if it is pressed, send a "busy, please wait" message to the host through the wireless transmission unit; if it is not pressed, whether the continue scanning function button S3 is pressed, if pressed When the button is pressed, the message "no one is in the house" is sent to the host through the wireless transmission unit; if not pressed, the program ends.
In this paper, the design of the wireless doorbell is realized through the control of the single-chip microcomputer, and the wireless data transmission of the master-slave control system is realized by using the wireless transceiver module, so that the wireless data transmission reduces the trouble caused by the wire connection, and does not affect the indoor appearance; The human body perception is realized, the voice chip completes the humanized voice prompt function, and the voice prompt circuit is used to give the outside visitor a response signal to the house situation, so that the outside can accurately know whether there are people in the house. This system is easy to operate and makes our life more humanized and intelligent.
The above is the details of the wireless doorbell solution introduced by Shenzhen Zuchuang Microelectronics Co., Ltd. to you. If you have the development and design needs of the wireless doorbell system, you can rest assured to entrust it to us. We have rich experience in custom development of electronic products, and 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, Bluetooth IC and module, wifi module. Our development capabilities cover PCB design, single-chip microcomputer development, Bluetooth technology development, software customization development, APP customization development, WeChat official account development and other hardware and software design. 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 development of electronic education products.
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