Specific realization function
The system consists of STC89C52 single-chip microcomputer + water level detection sensor + DS18B20 temperature probe sensor + button module + relay module + alarm and indication module + LCD1602 display module + power supply.
Specific functions:
1. The first line of the LCD1602 display shows the temperature and timing time, and the second line shows the upper and lower temperature limits;
2. The button can set the upper and lower limits of the temperature and the timing time; the timing time is up to start heating
3. Use two water level detection sensors to detect the water level: when the water level lower limit sensor detects water, the relay starts to control the water addition; when the water level upper limit sensor detects water, it stops adding water;
4. When the temperature is lower than the set lower limit temperature value, the relay starts to control heating; when the temperature is higher than the set upper limit temperature value, it stops heating.
design background
According to incomplete statistics, electric water heaters are the mainstay of urban households in our city, accounting for more than 60% of the total; gas water heaters, which used to be glamorous, are gradually eclipsed, with a market share of less than 20%; emerging solar water heaters have been installed Conditions are limited, but its safety and environmental protection performance is widely favored by consumers, and its development trend is rapid, with a market share of about 15%. Out of safety considerations, urban residents choose more electric water heaters and solar water heaters. The current commercial housing ventilation effect is not good, the pollution caused by gas cannot be eliminated in time, while electric water heaters and solar water heaters basically have no worries in this regard. The advantages of electric water heaters: easy to install, not affected by the weather, not restricted by floors and water supply pipes, and low input cost. With the advancement of technology and the development of new products, various installation forms of electric water heaters, such as under-mounted and embedded, have been listed successively, completely getting rid of the limitation of room space. In today's society, science and technology are changing with each passing day, water heater technology is developing rapidly, and more and more scientific and technological achievements are used in the manufacture of water heaters. Today's water heater products are definitely not a simple heater, but modern home appliances with high technological content. With the gradual improvement of the people's living standards in our country, their living conditions have been greatly improved, and there are endless varieties of water heaters that are closely related to family life, and they are renovated. It is under this background that this design chooses the design and research of smart electric water heater based on STC89C51 single-chip microcomputer.
The significance of this subject lies in the intelligent improvement of the water heater, the use of a single-chip microcomputer to control its water temperature and level parameters, which improves the stability of the water heater, and at the same time introduces the temperature sensor DS18B20 to collect data on the water temperature, which also improves the control of the system Accuracy, the control structure of the water level is simple, easy to realize, and has strong practical application value. Although it is an improvement to the water heater, this intelligent improvement method can also be applied to the environment of various water temperature and water level control in industry and life, and it also has a certain reference significance for the improvement of the control of other related parameters. The water temperature and water level measurement and control system based on the single-chip microcomputer is an improved intelligent product. With its own unique advantages of high control accuracy, good stability and low cost, it will have a wide range of practical value in the future. The improved method also has a wide range of applications.
hardware design
This subject is based on the design of the STC89C51 single-chip smart electric water heater controller. The control requirements to be achieved are: (1) LCD1602 liquid crystal display water temperature, setting the upper and lower limits and timing time, (2) the water temperature detection display range is 00～99 ℃, the accuracy is ±1℃. (3) The preset temperature range is 0～99℃. When the detection temperature is lower than the preset temperature, heating starts; when the detection temperature is higher than the preset temperature, heating stops. (4) Set up 4 program buttons. Ask to set the key, plus key, minus key, and OK respectively.
software design
The software design consists of three parts: the main program, the key scanning subprogram and some other functional module subprograms. The main controller subroutine includes A/D conversion subroutine (water level, water temperature), keyboard processing and display subroutine, temperature control subroutine (using output comparison function), and leakage protection subroutine. The main program must first initialize the working mode parameters of the timer, COP module, A/D conversion, port, key interrupt and other parts of the single-chip microcomputer. After that, the main program loop of the system can call the subroutines of each functional module, and the related The processing of the event is realized by the flag bit and the judgment flag bit.
Schematic diagram
The system schematic design adopts Altium Designer19, as shown in the figure.
program
This design uses KEIL5 software to realize the program design, as shown in the figure.
Simulation implementation
This design uses protues8.7 software to realize the simulation design, as shown in the figure.
All information
All materials include programs (notes), AD schematic diagrams, protues simulation, reference papers, program explanations, simulation explanations, simulation videos, schematic explanations, introduction to the use of materials, etc., the most complete in the entire network!
