72 lines
1.5 KiB
C
72 lines
1.5 KiB
C
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/*
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*
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* MH-Z14B CO2 Sensor
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* Based on Raspberry Pi wiringPi library
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* Time: 20240109
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*
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*/
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#include <stdio.h>
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#include <wiringPi.h>
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#include <wiringSerial.h>
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#include <unistd.h>
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// 校准
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static void calibration(int fd)
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{
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// 校准传感器零点（ZERO）
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char zero[9] = { 0XFF, 0X01, 0X87, 0X00, 0X00, 0X00, 0X00, 0X00, 0X78 };
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write(fd, zero, 9);
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delay(200);
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return;
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}
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int main()
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{
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int fd = 0;
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char checksum = 0;
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int High = 0;
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int Low = 0;
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int ppm = 0;
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char read_command[9] = { 0xFF, 0x01, 0x86, 0x00, 0x00, 0x00, 0x00, 0x00, 0x79 };
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char data[9] = { 0 };
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if ((fd = serialOpen("/dev/serial0", 9600)) < 0) {
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printf("Unable to open device\n");
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return 1;
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} else {
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printf("ttyAMA0 initialised ok\n");
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}
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while (1) {
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// 写入读取命令
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write(fd, read_command, 9);
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delay(100);
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// 读取
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read(fd, data, 9);
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checksum = (0xFF - (data[1] + data[2] + data[3] + data[4] + data[5] + data[6] + data[7])) + 1;
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High = (int)data[2];
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Low = (int)data[3];
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ppm = (256 * High) + Low;
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if (data[8] == checksum) {
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for (int loop = 0; loop <= 8; loop++) {
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printf("data%d: %X\n", loop, data[loop]);
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}
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printf("checksum: %X = %X\n", data[8], checksum);
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printf("CO2 Concentration: %d ppm\n\r\n", ppm);
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} else {
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calibration(fd);
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continue;
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}
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delay(3000);
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}
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return 0;
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}
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