motion_activated_fogger_controller.ino

  
    // Handy defines for readability
    #define TURN_LED_ON HIGH
    #define TURN_LED_OFF LOW
    #define TURN_FOGGER_ON LOW
    #define TURN_FOGGER_OFF HIGH
    #define MOTION_DETECTED HIGH
    #define NO_MOTION_DETECTED LOW
    #define SAMPLE_DELAY_MS 10 

    
    int LED_OUTPUT_PIN = 13;                // specify output pin for LED, for debugging purposes while fogger not attached
    int FOGGER_RELAY_OUTPUT_PIN = 3;               // output pin for relay to turn fogger on
    int IR_SENSOR_INPUT_PIN = 7;           // input pin for motion sensor
    int previousSensorState = NO_MOTION_DETECTED;          // start with no motion detected
    int currentSensorValue = 0;    // variable for reading IR sensor status
    int FOGGER_ON_TIME_MS = 30000;  // 30 seconds "on" time
    int FOGGER_REPLENISH_TIME_MS = 60000; // timeout while motion won't be acted on
     
    void setup()
    {
      pinMode(LED_OUTPUT_PIN, OUTPUT);  
      pinMode(FOGGER_RELAY_OUTPUT_PIN, OUTPUT); 
      pinMode(IR_SENSOR_INPUT_PIN, INPUT);
     
      Serial.begin(9600);
    }

// Loop to detect and act on motion.  If motion is detected, turn on fogger for FOGGER_ON_TIME.
// Then, force a delay of FOGGER_REPLENISH_TIME to ensure fogger will be ready before motion is acted upon.
     
    void loop()
    {
      currentSensorValue = digitalRead(IR_SENSOR_INPUT_PIN);
      if (currentSensorValue == MOTION_DETECTED) {
        digitalWrite(LED_OUTPUT_PIN, TURN_LED_ON);
        digitalWrite(FOGGER_RELAY_OUTPUT_PIN, TURN_FOGGER_ON);
        if (previousSensorState == NO_MOTION_DETECTED)
        {
          previousSensorState = MOTION_DETECTED;
          Serial.println("Turning on fogger");
          delay(FOGGER_ON_TIME_MS);
          Serial.println("Turning off fogger");
        }
        delay(SAMPLE_DELAY_MS);
      }
      else 
      {
        digitalWrite(LED_OUTPUT_PIN, TURN_LED_OFF); 
        digitalWrite(FOGGER_RELAY_OUTPUT_PIN, TURN_FOGGER_OFF); 
        if (previousSensorState == MOTION_DETECTED)
        {
          previousSensorState = NO_MOTION_DETECTED;
          Serial.println("Wait for fogger to replenish");
          delay(FOGGER_REPLENISH_TIME_MS);
          Serial.println("Fogger is ready");
        }
      }
    }