Download: file
/* /////////////////////////////////////
 * Mistletoe Code modified by Leslie Birch with huge thanks to PIRsense Code from Arduino Playground
 * The base code is for the Parallax PIR Sensor, which is similar to the Adafruit PIR Sensor
 * @author: Kristian Gohlke / krigoo (_) gmail (_) com / http://krx.at
 * @date:   3. September 2006 
 *
 * kr1 (cleft) 2006 
 * released under a creative commons "Attribution-NonCommercial-ShareAlike 2.0" license
 * http://creativecommons.org/licenses/by-nc-sa/2.0/de/
 *
 *
 * The sensor's output pin goes to HIGH if motion is present.
 * However, even if motion is present it goes to LOW from time to time, 
 * which might give the impression no motion is present. 
 * This program deals with this issue by ignoring LOW-phases shorter than a given time, 
 * assuming continuous motion is present during these phases.
 *  
 */

/////////////////////////////
//VARS
//the time we give the sensor to calibrate (10-60 secs according to the datasheet)
int calibrationTime = 30;        

//the time when the sensor outputs a low impulse
long unsigned int lowIn;         

//the amount of milliseconds the sensor has to be low 
//before we assume all motion has stopped
long unsigned int pause = 2000;  

boolean lockLow = true;
boolean takeLowTime;  

int pirPin = 0;    //the digital pin connected to the PIR sensor's output
int ledPin1 = 1;
int ledPin2 = 2;
int ledPin3 = 3;
int ledPin4 = 4;


/////////////////////////////
//SETUP
void setup(){
  //Serial.begin(9600);
  pinMode(pirPin, INPUT);
  pinMode(ledPin1, OUTPUT);
  pinMode(ledPin2, OUTPUT);
  pinMode(ledPin3, OUTPUT);
  pinMode(ledPin4, OUTPUT);
  digitalWrite(pirPin, LOW);

  //give the sensor some time to calibrate
  //Serial.print("calibrating sensor ");
    for(int i = 0; i < calibrationTime; i++){
    //  Serial.print(".");
      delay(1000);
      }
   // Serial.println(" done");
   // Serial.println("SENSOR ACTIVE");
    delay(50);
  }

////////////////////////////
//LOOP
void loop(){

     if(digitalRead(pirPin) == HIGH){
       digitalWrite(ledPin1, HIGH);   //the led visualizes the sensors output pin state
       delay (200);
       digitalWrite(ledPin3, HIGH);   //the led visualizes the sensors output pin state
       delay (400);
       digitalWrite(ledPin2, HIGH);   //the led visualizes the sensors output pin state
       delay (200);
       digitalWrite(ledPin4, HIGH);   //the led visualizes the sensors output pin state
       if(lockLow){  
         //makes sure we wait for a transition to LOW before any further output is made:
         lockLow = false;            
        // Serial.println("---");
        // Serial.print("motion detected at ");
        // Serial.print(millis()/1000);
       //  Serial.println(" sec"); 
         delay(50);
         }         
         takeLowTime = true;
       }

     if(digitalRead(pirPin) == LOW){       
       digitalWrite(ledPin4, LOW);  //the led visualizes the sensors output pin state
       delay (200);
       digitalWrite(ledPin2, LOW);  //the led visualizes the sensors output pin state
       delay (400);
       digitalWrite(ledPin3, LOW);  //the led visualizes the sensors output pin state
       delay (200);
       digitalWrite(ledPin1, LOW);  //the led visualizes the sensors output pin state

       if(takeLowTime){
        lowIn = millis();          //save the time of the transition from high to LOW
        takeLowTime = false;       //make sure this is only done at the start of a LOW phase
        }
       //if the sensor is low for more than the given pause, 
       //we assume that no more motion is going to happen
       if(!lockLow && millis() - lowIn > pause){  
           //makes sure this block of code is only executed again after 
           //a new motion sequence has been detected
           lockLow = true;                        
           //Serial.print("motion ended at ");      //output
           //Serial.print((millis() - pause)/1000);
          // Serial.println(" sec");
           delay(50);
           }
       }
  }
This guide was first published on Dec 18, 2014. It was last updated on Dec 18, 2014. This page (Code) was last updated on Sep 13, 2019.