Virtual IoT Lab DEI

Instructions

Objective:

Learn to use the MQ135 air quality sensor to detect harmful gases (CO2, ammonia, benzene, smoke) and display air quality levels with visual indicators (RGB LED) and audio alerts (buzzer).

Steps to Perform:

Click 'Start Simulation' to power the circuit
Click 'Add Smoke' to introduce pollutants
Use the slider to increase Smoke Intensity
Watch the Buzzer Warning indicator near the slider
Once level crosses 66%, the Buzzer will start beeping
Click 'Stop Simulation' to reset the circuit

Key Concepts:

MQ135 Sensor: Connected to Analog Pin A1. It detects smoke and gases.
Buzzer: Connected to Digital Pin 10. Triggers when pollution is dangerous.
Threshold Alert: Code monitors sensor and triggers alarm at > 66%.

Arduino Code

          /* 
  MQ135 Gas Sensor with Buzzer Alert
  Sensor: Pin A1
  Buzzer: Pin 10
*/

#define SENSOR_PIN A1
#define BUZZER_PIN 10
#define THRESHOLD 66

void setup() {
  Serial.begin(9600);
  pinMode(BUZZER_PIN, OUTPUT);
}

void loop() {
  int sensorValue = analogRead(SENSOR_PIN);
  
  // Mapping 0-1023 to 0-100%
  int pollutionLevel = map(sensorValue, 0, 1023, 0, 100);
  
  Serial.print("Pollution: ");
  Serial.print(pollutionLevel);
  Serial.println("%");

  if (pollutionLevel > THRESHOLD) {
    tone(BUZZER_PIN, 800); // Beep beep!
    delay(200);
    noTone(BUZZER_PIN);
    delay(200);
  } else {
    noTone(BUZZER_PIN);
  }
  
  delay(100);
}
            
        