Appliance network remote control

Application of bluetooth technology in constructing centralized remote control of electric appliance network

The 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 system

1.1 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 structure

The 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 Topology

The 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 technology

Authentication 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 appliances

Through 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.

Summarize

Compared 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.