Introduction: Valentines Day Motion Activated LED Heart

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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

Step 2: Tools

• 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 • Computer • Arduino micro USB cable • Paper glue • Arduino software

Step 3: The Circuit for the LEDs

For the LEDs : Connect all negatives with negatives and all positives with positives, then connect the positive side to Arduino pin 12, connect the positive side to Arduino ground. When you have finished, snap in the LEDs into their holders, and hot glue them so that they stay in place.

Step 4: The Circuit for the PIR Sensor

For the PIR sensor: Connect GND to Arduino ground. Connect VCC to Arduino 5 volts. Connect OUT to Arduino pin 3. When you have finished, hot glue the PIR sensor into the hole.

Step 5: Completed Circuit

Solder the 40 pin IC socket to the PC board and make the connections

Step 6: Cutting Out the Shape

To cut out the shape of the heart you will first have to trace a heart and then cut it out on cardboard. After that, cut out the same shape but just on red paper. After you have finished that, glue them together

Step 7: PIR Drilling

First drill out the big hole for the PIR sensor in the middle of the heart.

Step 8: LED Holder Drilling

Now with the small drill bit, drill out 16 small holes around the heart, so that the LED holders fit snug. So that you only have to snap the LEDs in the heart, instead of gluing them.

Step 9: Wire Bending

With the coat hanger, cut out a strip of metal wire, and bend it so that it fits around the heart. Then hot glue it.

Step 10: The Code

So now that your circuit is completed, lets get ready to upload the code to the Arduino micro The code: * //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; ///////////////////////////// //SETUP void setup(){ Serial.begin(9600); 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.print("."); delay(1000); } Serial.println(" done"); Serial.println("SENSOR ACTIVE"); delay(50); } //////////////////////////// //LOOP void loop(){ if(digitalRead(pirPin) == HIGH){ digitalWrite(ledPin, 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(ledPin, 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); } } }