‫/* ‫
‫ MQ ‫
‫*/ ‫
‫ ‫
‫const int LED = 2; ‫
‫const int DO = 8; ‫
‫ ‫
‫void setup() { ‫
‫ Serial.begin(9600); ‫
‫ pinMode(LED, OUTPUT); ‫
‫ pinMode(DO, INPUT); ‫
‫} ‫
‫ ‫
‫void loop() { ‫
‫ ‫
‫ int alarm = 0; ‫
‫ float sensor_volt; ‫
‫ float RS_gas; ‫
‫ float ratio; ‫
‫ //-Replace the name "R0" with the value of R0 in Calibration Proces ‫
‫ float R0 = 0.95; ‫
‫ ‫
‫ int sensorValue = analogRead(A0); ‫
‫ sensor_volt = ((float)sensorValue / 1024) * 5.0; ‫
‫ RS_gas = (5.0 - sensor_volt) / sensor_volt; // Depend on RL on yor module ‫
‫ ratio = RS_gas / R0; // ratio = RS/R0 ‫
‫ //------------------------------------------------------------/ ‫
‫ Serial.print("sensor_volt = "); ‫
‫ Serial.println(sensor_volt); ‫
‫ Serial.print("RS_ratio = "); ‫
‫ Serial.println(RS_gas); ‫
‫ Serial.print("Rs/R0 = "); ‫
‫ Serial.println(ratio); ‫
‫ ‫
‫ Serial.print("\n\n"); ‫
‫ ‫
‫ alarm = digitalRead(DO); ‫
‫ if (alarm == 1) digitalWrite(LED, HIGH); ‫
‫ else if (alarm == 0) digitalWrite(LED, LOW); ‫
‫ delay(1000); ‫
‫ ‫
‫}