【Sun Yat-sen University Competition】--Remote relay control panel

Team information: Novice team: Wu Strontium Yu and Deng Kaiyun. The winning entry in the electrical design competition of Sun Yat-sen University - remote relay control board 1. Design goal: Design and produce a remotely controllable relay board. 2. Overall system block diagram ① Overall scheme description This design scheme is divided into two parts for design, one is the transmitting end and the other is the receiving end. (Ⅰ) Transmitter The transmitter uses WeMos D1 and Esp8266nodemcu as the main control board. Both main control boards are connected to the 2.4G wireless module nrf24l01 and LED lights. The nrf24l01 is used to communicate with the receiving end and send data to the receiving end. , LED lights are used to reflect the working conditions of the system. (Ⅱ) Receiver The receiver uses two Arduino Uno development boards as the main control board. Both main control boards are connected to the 2.4G wireless module nrf24l01 and relays (one of the arduino boards is connected to two relays and two nrf24l01), nrf24l01 is used to communicate with the transmitter, receive the data sent by the transmitter, and send information to the main control board through the received data. The main control board can then control the relay to open or close through the information. ② Overview of the selection of the plan: After a long period of thinking in the early stage, our team searched for information on the Internet and compared different control boards and electronic components, and finally designed a plan with esp8266-Arduino-nrf24l01 as the main body, and finally decided on it. Develop a design plan. Selection of control boards: Use two main control boards at both the transmitter and receiver. The reason is that if only one main control board is used at both the transmitter and receiver, the system will be unstable or even unable to work. Using two control boards at both the transmitter and receiver can improve the efficiency of the system. Relay selection: The relay model selected for this design is SRD-05VDC-SL-C, which has been welded to the prepared adapter board. There are three pins on the adapter board: Vcc, GND, and I/O. To control the operation of the relay, an LED light is also welded to show whether the relay is energized and whether it is in working condition. 3. Network topology ① Comparison of communication methods and selection The communication module of this design scheme uses a combination of esp8266 and nrf24l01. At the beginning, we compared the performance parameters of esp8266 and other WiFi modules. In the end, because esp8266 is easy to use and there are ready-made main control boards with esp8266 available, we chose esp8266 as the WiFi module of this design. Regarding the choice of 2.4G wireless module nrf24l01, the big reason is that it has a long transmission distance, almost no delay, and is easy to develop. If the delay time is too long in actual engineering applications, it will affect production efficiency, so nrf24l01 was finally chosen as the 2.4G Wireless module for communication between remote control and relay. ②Topological structure description (Ⅰ) This design scheme uses a total of 6 nrf24l01, 3 transmitters, 2 of which are located on the Esp8266nodemcu main control board, 1 is located on the WeMos D1 main control board, and 3 receivers are located on different Arduino Uno board. Each two nrf24l01 corresponds to each other and transmits and receives data respectively, and due to different communication channels and addresses, they do not interfere with each other. (Ⅱ) At the transmitter end, we connected an LED light to the WeMos D1 main control board, and connected two LED lights in parallel to the Esp8266nodemcu main control board. The colors of these three LED lights are different from each other, reflecting the differences of the receiving end. the working status of the relay. (III) The network topology of the receiving end has been described in detail in the receiving end described in the overall system scheme above, and will not be repeated here. 4. Application layer communication protocol design and description. The communication components of this solution are esp8266 and nrf24l01. The esp8266 communication uses the Http application layer communication protocol. Data is sent and received between the browser and the Web server on the Internet through HTTP. Enable communication. The communication of nrf24l01 is to achieve communication between different nrf24l01 by setting different communication channels and communication addresses.