Digit Squad - March 2016

    /*
     * Turn ON the LED if motion detected
     * Turn OFF the LED if no motion detected
     * Commented by Praneet Sah
     * this code is famously used for showing PIR sensor's usage
     */

    int ledPin = 13;                // This LED is embedded in your Arduino
    int inputPin = 8;               // Choose the input pin (for PIR sensor)
    int pirState = LOW;             // we start, assuming no motion detected
    int val = 0;                    // variable for reading the pin status

    void setup() {
      pinMode(ledPin, OUTPUT);      // declare LED as output
      pinMode(inputPin, INPUT);     // declare sensor as input

      Serial.begin(9600);
    }

    void loop(){
      val = digitalRead(inputPin);  // read input value of the sensor
      if (val == HIGH) {            // check if the sensor's input is HIGH
        digitalWrite(ledPin, HIGH);  // then turn LED ON
        if (pirState == LOW) {      // if first loop, then pirState will be LOW unless val changes to LOW

          Serial.println("Motion detected!"); //Tell user that motion detected!

          pirState = HIGH; //Setting pirState to HIGH so that so that if 'val' remains HIGH then we won't spam the user with the previous line
        }
      } else {
        digitalWrite(ledPin, LOW); // val is LOW and thus the turn LED OFF
        if (pirState == HIGH){      //

          Serial.println("Motion ended!"); // Tell user that NO motion detected!

          pirState = LOW; // Setting pirState to LOW so that so that if 'val' remains LOW then we won't spam the user with the previous line
        }
      }
    }