/* Arduino MQ4 gas sensor - Geekstips.com This example is for calculating R0 which is the resistance of the sensor at a known concentration without the presence of other gases, or in fresh air */ void setup() { Serial.begin(9600); //Baud rate } void loop() { float sensor_volt; //Define variable for sensor voltage float RS_air; //Define variable for sensor resistance float R0; //Define variable for R0 float sensorValue; //Define variable for analog readings for (int x = 0 ; x < 500 ; x++) //Start for loop { sensorValue = sensorValue + analogRead(A0); //Add analog values of sensor 500 times } sensorValue = sensorValue / 500.0; //Take average of readings sensor_volt = sensorValue * (5.0 / 1023.0); //Convert average to voltage RS_air = ((5.0 * 10.0) / sensor_volt) - 10.0; //Calculate RS in fresh air R0 = RS_air / 4.4; //Calculate R0 Serial.print("R0 = "); //Display "R0" Serial.println(R0); //Display value of R0 delay(1000); //Wait 1 second } ``` 其他參考:
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