202 1-05-23 Deng Ran Shao Xinyu Yu Jianguang Zhu Yingkun
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Keywords: wireless communication refrigerator microcontroller
Deng Ran Shao Xinyu Yu Jianguang Zhu Yingkun
The increasing development of Internet technology has driven the market share of smart refrigerators, and the access of home appliances to the Internet of Things has entered a high-speed market-oriented development period, and smart home appliances with wireless communication modules have ushered in a development period. Smart refrigerator can switch between different modes, automatically adapt to different environments, and always keep the best storage state of food. Through computer or mobile phone, you can monitor the quantity and quality of food in the refrigerator, provide users with healthy recipes, place orders to supplement ingredients and share food through the internet. The purpose of this system is to design an intelligent refrigerator system. High-performance STM32 single chip microcomputer is selected to build the system, so that the environmental parameters in the refrigerator are kept constant, and the data can be viewed by intelligent means. Using DS 18B20 sensor to measure the freezing chamber temperature. DHT 1 1 sensor can measure the temperature and humidity in the fresh-keeping room, and you can check the current temperature and humidity through the screen. According to the measurement results, the equipment is automatically started to realize refrigeration and defrosting. Through Wifi wireless communication, terminal devices can view data.
Keywords: refrigerator; Temperature; Single chip microcomputer; wireless communication
1 Introduction
1. 1 background and significance of project research
With people's increasing dependence and demand for intelligent new technologies. Smart home has become the goal that people pursue. Smart home takes family residence as a platform, and applies a variety of mature technologies, intelligent hardware and intelligent terminals to form a smart home system. At present, with the rapid development of the national economy, under the requirements of energy saving, emission reduction, environmental protection and low carbon, smart home control equipment has gradually become the focus of the future development of the residential industry.
1.2 Research Status of Intelligent Refrigerator
The research on smart home abroad started from 1980, and it has developed for more than 30 years now, which started earlier than that in China and experienced four technological changes.
The third smart home technology is the most widely used smart home product, which realizes the unified control of all devices in the home. The fourth technology is IP technology, which is already available in some developed countries and has corresponding products.
20 13 In April, Samsung introduced a smart refrigerator named T9000. In addition to the four-door design in appearance, the most eye-catching thing is that the refrigerator is loaded with Android system. The door of the refrigerator is equipped with a 10-inch touch screen, which supports WiFi network connection and comes with a note-taking application Evernote.
Hisense also launched the Bona SMART refrigerator on 20 12 1 1. This refrigerator can be equipped with IOT cloud service and introduce new food management functions. In 20 15, Haier released a "new kitchen" internet smart refrigerator with 10 inch screen and stereo speakers. Through this electronic screen, audio-visual entertainment, life consultation and online interaction can be carried out.
Main research contents of 1.3
The design and implementation of intelligent refrigerator based on single chip microcomputer, DS 18B20 temperature sensor collects the temperature in the refrigerator, DHT1temperature and humidity sensor collects the temperature and humidity in the refrigerator, and transmits the data to STM32F 103 main control unit module, and organic light-emitting diode LCD displays the data. According to different data, the refrigeration equipment and defrosting equipment are controlled, and the data are wirelessly transmitted to the terminal equipment for display, so as to achieve the effect of constant temperature and humidity.
2. Overall scheme design of intelligent refrigerator
According to the characteristics of smart refrigerators, the data transmission of home refrigerators requires that the communication mode has the characteristics of small data volume, short transmission distance, many nodes and high safety factor, while wireless communication has the characteristics of self-organization, multi-nodes, low power consumption and short delay, which is undoubtedly the best choice for smart home intranet communication mode. Therefore, the combination of wireless communication modes such as WiFi is adopted in smart home communication mode.
2. 1 system analysis
The system mainly consists of the following parts: intelligent refrigerator, remote server and intelligent mobile terminal (smart phone or PAD). The system takes STM32F 103 single chip microcomputer as the control core, adopts DHTIl digital temperature sensor to collect temperature signals, and sends them to single chip microcomputer for processing and display. Then the data is sent to the serial-to-Wi-Fi data transmission module through the serial port of the single chip microcomputer, and the module sends and receives wireless data. The wireless router relays the routing, the remote server processes the sending and receiving data and communicates with the intelligent mobile terminal, and the intelligent mobile terminal performs remote control and remote status display on the refrigerator. The structure block diagram of intelligent refrigerator control system and wireless system is shown in Figure 2- 1.
2.2 wireless communication scheme selection
This system uses wireless communication mode to communicate, and transmits the data collected by the sensor to the mobile phone for display, and at the same time controls it through this wireless mode.
wireless network
WiFi is popular all over the world, which is inseparable from its inherent characteristics. Compared with other wireless communication technologies, WiFi has the advantages of fast transmission speed, extremely low power consumption, better wireless link and high signal reliability. The wireless communication scheme adopts Wifi wireless communication mode.
2.3 Smart refrigerator hardware selection
In the design of intelligent refrigerator system, hardware selection mainly includes controller chip, temperature sensor and WIFI chip. Different hardware can be selected for the same function, but good hardware is very important to the stability, power consumption and economic cost of the whole system, so the selection of hardware is very important for this research scheme.
2.3. 1 controller chip selection
The microprocessor has powerful functions, low price, working voltage of 2 ~ 3.6V, various power-saving modes, and ensures the application of low power consumption. The working environment temperature is -40℃ ~+80℃/-40℃ ~+ 105℃, which shows that it can run stably in winter and summer.
Mainly has the following advantages:
(1) Low cost
(2) Powerful
(3) Mature technology
(4) The power consumption is relatively low.
2.3.2 Selection of Temperature and Humidity Sensors in Refrigeration Room
DHT 1 1 Temperature and humidity sensor is also a temperature and humidity sensor with calibrated digital signal output. Digital module acquisition technology and temperature and humidity sensor technology ensure that the product has good reliability and stability. The DHT 1 1 temperature and humidity sensor is shown in Figure 2-3.
2.3.3 Selection of Temperature Sensor for Refrigerator
The freezer needs to freeze food, and the sensor with appropriate range should be selected for low temperature detection. DS 18B20 is a commonly used digital temperature sensor. Its output is a digital signal, which has the characteristics of small size, low hardware cost, strong anti-interference ability and high precision.
Wifi module selection
ATK-ESP8266 is a high-performance serial wireless module. It is equipped with ESP8266 module, which communicates with the main control chip through serial port to facilitate the connection with the main control chip. Finally, ATK-ESP8266 is selected as the WiFi module of the system.
2.4 system software selection
The development of STM32 main control chip adopts Keil u Vision5 development environment. Mainly aimed at ARM processors, especially those with ARM Cortex-M as the core. Keilu Vision5 is compatible with Keil u Vision4, and based on Keil u Vision4, it strengthens the support for Cortex-M microcontroller development, and divides the traditional development mode and interface into MDK kernel and software package.
After scheme discussion, the design scheme of intelligent refrigerator system is finally determined. The hardware block diagram is shown in Figure 2-6.
3 system software design
In this paper, when developing STM32 master chip, Keil u Vision5 development environment is selected for software design. JLINK simulator is used for research. In the process of system design, the modular design idea is applied, that is to say, every link in the system is played by the call of sub-functions.
3. 1 Overall software design
Keil u Vision5 is an integrated development tool launched by Keil Company in June 20 13, mainly for using u Vision5 IDE. Mainly aimed at ARM processors, especially those with ARM Cortex-M as the core.
Keilu Vision5 is compatible with Keil u Vision4, and based on Keil u Vision4, it strengthens the support for Cortex-M microcontroller development, and divides the traditional development mode and interface into MDK kernel and software package.
JLINK emulator is a JTAG emulator introduced by SEGGER Company, which is mainly used to support the simulation of ARM core chips, and can support the simulation of most ARM series cores in various integrated development environments such as KEIL and ADS.
4 conclusion
This paper designs a simple, practical and low-cost intelligent refrigerator system. The system adopts STM32 as the hardware platform and cooperates with embedded operating system to realize the basic functions of intelligent control. The system does not pursue gorgeous appearance, mainly because it is low in price, simple and practical, and mainly focuses on the low-end market. This paper designs an intelligent refrigerator system. Based on Wifi wireless communication technology, the system has realized a complete set of equipment and control management system integrating control and information management, such as temperature and humidity information collection of food environment in the refrigerator, remote adjustment and monitoring of the temperature in the cold room and freezer, information prompt function, data storage and so on. It has the advantages of safety, reliability, low energy consumption, good preservation effect and health.
refer to
[1] Hong Sean, Chen Gong. Research on intelligent interactive design strategy of refrigerator network [J]. Development and innovation of electromechanical products, 2018,31(01):16-18+22.
[2], Jiao, Cui, Gao Donghua. Summarize the development status of smart refrigerators [J]. Household appliance technology, 20 15, (1 1): 24-25.
Subject category: 202 1, the key subject of educational science in Heilongjiang province during the 14 th Five-Year Plan.
Title: Exploration on the Training Mode of Internet of Things Engineering Professionals Based on AIOT under the New Engineering Background
The project number is GJB1421618.
Harbin Huade College Harbin, Heilongjiang 150028