【IoT Graduation Project】esp8266+Gizwits AIoT+Remote Intelligent Control of Water Heater

毛球大大

【IoT Graduation Project】esp8266+Gizwits AIoT+Remote Intelligent Control of Water Heater [Copy link]

Abstract: A remote control system for water heaters is designed. With the help of Gizwits IoT development platform, the controller is connected to the cloud through the ESP8266WiFi module. The control system uses STM32F103ZET6MCU as the main control chip, ESP8266WiFi module as the communication interface, and solid-state relays to control the switches of the heater and pump. Users can control the water temperature and water level of the system through the indoor controller and mobile phone APP. After testing, the system has the advantages of safety, reliability, and simple operation, and has high practicality and broad application prospects.

With the development of the Internet, the Internet of Things has gradually become one of the themes of intelligent life. Traditional home appliances are developing in the direction of intelligence, and electric water heaters are no exception. In the past, remote control systems were divided into two categories: one is the GSM network; the other is the CDMA network, but the charges for both are too high and cannot be used for a long time, and they have not been well popularized. With the rapid development of the Internet and smart phones, smart phones are used as mobile terminals and applied to traditional electric water heaters. With the help of the Gizwits IoT development platform, a set of water heater remote intelligent control system is designed. This system has the advantages of simple installation, low price, real-time two-way monitoring of mobile phone APP and indoor controller, and uses the open Android and Gizwits IoT platform, which makes the system function expansion and product upgrade very convenient.

1 Overall plan of the system

The water heater remote intelligent control system adopts a two-way control mode of indoor control and mobile phone APP remote control. The overall framework of the system is as follows

The system mainly consists of five parts: temperature sensor, water level sensor, indoor controller, cloud, mobile APP and heating and pumping system. As the client, the indoor controller and mobile APP receive various control commands from users, send data to the cloud through WIFI network after processing, and provide real-time feedback on the execution status, displaying the system water temperature and water level information and the switch status of water heater heating and pumping.

The server is composed of the ESP8266WiFi module and its controller, which uses a large-coverage, high-reliability, and low-cost wireless network to achieve handshake and data transmission with the client; the controller and the server share an MCU, which converts the received user instructions into control commands, and displays the collected water temperature and water level data to the user in an intuitive and friendly manner through the indoor controller and mobile phone APP, and waits for the user's next instruction, thereby realizing real-time monitoring of the entire system.

2 System Hardware Design

The hardware structure frame of this system mainly consists of four parts: temperature sensor, water level sensor, indoor controller and ESP8266wifi module.

(1) Temperature sensor: This system uses NTC waterproof thermistors with negative temperature coefficient, high sensitivity and high precision as temperature sensors. The thermistor is connected in series with a known resistor, and the resistance of the thermistor is determined by the voltage divider ratio, and then the corresponding temperature can be converted by the thermistor calculation formula.

(2) Water level sensor: This system uses a waterproof US-100 ultrasonic ranging module as a water level sensor. This module can achieve a non-contact ranging function of 2cm-4.5m, has low power consumption, comes with temperature correction, and has multiple communication methods such as GPIO and serial port. It has a built-in watchdog and works stably and reliably.

(3) Indoor controller: mainly composed of a 2.4-inch LCD screen and 5 function buttons.

(4) ESP8266-WiFi module: It is an ultra-low power UART-WIFI transparent transmission module designed for mobile devices and IoT applications. It can connect the user's physical device to the WiFi wireless network, communicate with the Internet or local area network, and realize networking functions.

3. System software design

The software design of this system is divided into three parts: data acquisition, data transmission between the controller and the cloud, and human-computer interaction. The human-computer interaction is set according to the function and will not be explained here.

The main working process of the data acquisition part is as follows: first, the system is initialized. The temperature acquisition uses the 12-bit ADC built into the STM32F103ZET6 to measure its analog voltage value. After a series of data conversions, the corresponding temperature value is obtained, and then a relatively stable temperature value is obtained through median and mean filtering. For water level acquisition, the UARST3 of the STM32F103ZET6 is used to receive the distance value sent by the serial port of the US-100 ultrasonic ranging module, and then a more accurate water level value can be obtained through a series of data processing and mean filtering.

The data transmission between the controller and the cloud is mainly through the Gizwits IoT cloud platform. You can develop your own products, set relevant data points according to your needs, and then develop through MCU, select the appropriate development plan and hardware platform, and then automatically generate code. Finally, port the code to the system program.

4 Test results

The system was debugged and tested in the laboratory to control the water level and temperature in the water tank. The test showed that the water level and temperature in the water tank of the system can be monitored in real time and in both directions, whether in the indoor controller or the mobile phone APP. The water temperature and water level are accurately controlled, with the water temperature error within +1 degree Celsius and the water level error within +1cm. It meets the accuracy requirements of household water heaters.

5 Conclusion

This system is a remote intelligent control system for water heaters designed based on the Gizwits IoT development platform. It has the characteristics of real-time two-way monitoring and low cost. After testing, the system solution is feasible, the circuit is safe and reliable, and the control accuracy meets the requirements. The system has high stability. At the same time, the system is highly scalable, such as being able to monitor multiple home appliances at the same time or more functional modes, which need further research and discussion.

Honghuzaitian

I feel that it is more interesting to use home appliances connected to the Internet as rice cookers, after all, you can start cooking remotely.