Picture of Valentines Day Motion Activated LED Heart
This heart will light up whenever it senses motion through the Passive Infrared (PIR) sensor. We will be using the PIR sensor as an input and the LEDs as outputs.

Step 1: Materials

•PIR motion sensor (1) •Arduino micro (1) •Red LEDs (16) •Coat hanger(1) •Jumper wires •PC board •Cardboard •5mm LED holders(16) •Red paper •40 pin IC socket(1) • Servo cable • 3 break away pins
arduino 123 (author) 2 years ago
sorry that i could not edit this page and use bullet form:

* Soldering iron
* Hot glue
* Scissors
* Solder
* Pliers
* Wire strippers and cutters
* Drill
* Drill bit as big as PIR sensor
* Drill bit as big as LED
* Arduino micro USB cable
*Paper glue
* Arduino software
arduino 123 (author) 2 years ago
sorry i could not edit this page and put it in bullet form :

*PIR motion sensor (1)
*Arduino micro (1)
*Red LEDs (16)
*Coat hanger(1)
*Jumper wires
*PC board
*5mm LED holders(16)
*Red paper
*40 pin IC socket(1)
* Servo cable
* 3 break away pins
arduino 123 (author) 2 years ago
Sorry for the look of the code above - I sent it via mobile and it lost indentation. I tried to update the page but got "There's been a problem updating your Instructable
parsererror SyntaxError: Unexpected token P"....Here it again.

* //////////////////////////////////////////////////
* //making sense of the Parallax PIR sensor's output
* //////////////////////////////////////////////////
* Switches a LED according to the state of the sensors output pin.
* Determines the beginning and end of continuous motion sequences.
* @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 Parallax PIR Sensor is an easy to use digital infrared motion sensor module.
* (http://www.parallax.com/detail.asp?product_id=555-28027)
* 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.

//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 = 5000;

boolean lockLow = true;
boolean takeLowTime;

int pirPin = 3; //the digital pin connected to the PIR sensor's output
int ledPin = 12;

void setup(){
pinMode(pirPin, INPUT);
pinMode(ledPin, OUTPUT);
digitalWrite(pirPin, LOW);

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

void loop(){

if(digitalRead(pirPin) == HIGH){
digitalWrite(ledPin, HIGH); //the led visualizes the sensors output pin state
//makes sure we wait for a transition to LOW before any further output is made:
lockLow = false;
Serial.print("motion detected at ");
Serial.println(" sec");
takeLowTime = true;

if(digitalRead(pirPin) == LOW){
digitalWrite(ledPin, LOW); //the led visualizes the sensors output pin state

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");