6-PM2.5 detection and alarm system based on 51 single chip microcomputer

Specific implementation functions

The system consists of STC89C52 microcontroller + ADC0832 + GP2Y1010AUPM2.5 sensor + button + LED and buzzer.

Specific functions:

1. The first line of the LCD displays the actual PM2.5 value, and the second line of the LCD displays the PM2.5 alarm threshold;

2. Button Description: The minus and plus keys are used to set the PM2.5 alarm threshold;

3. The PM2.5 alarm threshold can be set, with power-off saving function, no need to reset after power-on;

4. When the PM2.5 value is higher than the alarm threshold, the sound and light alarm will start.

design background

In recent years, the haze problem has become more and more serious, and government departments at all levels have attached increasing importance to it. In major haze pollution areas, various cities have established professional haze monitoring stations to better monitor the environmental PM2.5 and PM10 values ​​in this area, providing a basis for reporting, researching and controlling haze.

However, the current haze monitoring stations cover a limited area, and there are problems with inability to measure or large measurement errors in specific, smaller areas. Therefore, environmental protection personnel and researchers have studied and analyzed the composition of haze components, and at the same time, they have developed and designed many portable PM2.5 monitoring instruments using the simple, convenient and functional characteristics of the single-chip microcomputer system, so that the air pollution index can be monitored in more areas. After years of research and development, this type of simple PM2.5 monitoring equipment has been widely used in many fields and has been continuously improved. We firmly believe that with the attention of departments at all levels to haze control and the continuous development of related research, environmental governance work will be further improved, and one day, the motherland will be full of green waters and green mountains.

hardware design

The single-chip microcomputer minimum system, which consists of the chip, reset circuit, power supply circuit, crystal oscillator circuit, input and output circuit, etc., is the most important part of the single-chip microcomputer design, and is used to drive and control the expansion and operation of other modules. Figure 3.1 is the structure diagram of the single-chip microcomputer minimum system.

software design

The following is the programming idea for this program design:

(1) Define the value type, call the delay program, and define the data sending bit;

(2) PM2.5 measurement and A/D conversion program: Use the program to drive the dust sensor to monitor PM2.5 analog data and send it to ADC0832; at the same time, the AD module converts the analog quantity into digital quantity and sends it to the microcontroller for processing and display on the LCD screen;

(3) Pollution threshold setting and alarm design.

Schematic

The schematic diagram of this system was designed using Altium Designer19, as shown in the figure.

program

This design uses KEIL5 software to implement program design, as shown in the figure.

Simulation Implementation

This design uses protues8.7 software to implement simulation design, as shown in the figure.