Alcohol Gas Sensor (MQ-3)

/*
Here is an example code for the Alcohol Gas Sensor (MQ-3):

This code reads the alcohol concentration using the Alcohol Gas Sensor (MQ-3) and prints the result on the Serial Monitor of the Arduino IDE. The analog value from the sensor is converted to voltage using the formula voltage = sensor_value * (5.0 / 1023.0), where 5.0 is the voltage of the Arduino's power supply and 1023 is the maximum analog value. The voltage is then converted to resistance using the sensor's resistance and voltage divider, and the resistance is converted to alcohol concentration using the sensor's calibration curve.

To use this code, connect the Alcohol Gas Sensor (MQ-3) to an analog input pin of your Arduino board (usually A0 for most Arduino boards). The sensor should be powered with a 5V DC power source. Note that the accuracy of the alcohol concentration measurement can be affected by various factors, such as the temperature and humidity of the environment, and the calibration of the sensor.
*/

const int MQ3_pin = A0; // Pin connected to the analog output of the sensor

void setup() {
  Serial.begin(9600);
}

void loop() {
  // Read the analog value from the sensor
  int sensor_value = analogRead(MQ3_pin);

  // Convert the analog value to voltage (5V = 1023)
  float voltage = sensor_value * (5.0 / 1023.0);

  // Convert the voltage to resistance using the sensor's resistance and voltage divider
  float Rs = (5.0 - voltage) / voltage * 10000.0;

  // Convert the resistance to alcohol concentration using the sensor's calibration curve
  float alcohol_ppm = pow(10.0, (log10(Rs/10.0) - 1.1706) / -0.1619);

  // Print the alcohol concentration
  Serial.print("Alcohol concentration: ");
  Serial.print(alcohol_ppm);
  Serial.println(" ppm");

  // Wait for 1 second before taking the next reading
  delay(1000);
}