烟雾传感器MQ-2实验

实验现象

烟雾传感器把烟雾浓度值转换为模拟电压值输出，arduino通过A0引脚读取模拟电压值，通过串口发送给PC，当模拟电压值超过模块的比较器设定值，模块D0引脚输出低电平。arduino监控到D0引脚拉底信号时，板载LED点亮报警，串口输出Alarm信号。报警的阀值可以通过调节板载的电位器调整大小。

理论学习

VCC和GND之间加上5V电压

等待大概30s传感器预热后，读取模拟输出A0引脚电压

通过调节电位器，改变LED报警阀值

当浓度大于设定值时，模块上LED指示灯点亮，同时D0引脚输出低电平。

原理图

代码编写

#include<Arduino.h>#define sensor A5#define led 13#define sensor_d0 2unsigned int sensorvalue = 0;void setup() {// put your setup code here, to run once:pinMode(sensor_d0, INPUT);pinMode(sensor, INPUT);pinMode(led, OUTPUT);Serial.begin(9600);Serial.println("welcome to use");}void loop() {// put your main code here, to run repeatedly:sensorvalue = analogRead(sensor);Serial.print("ad value = ");Serial.println(sensorvalue);if (digitalRead(sensor_d0) == LOW) {Serial.println("alarm");digitalWrite(led, HIGH);} else {digitalWrite(led, LOW);}delay(1000);}