Arduino with PIR sensor

PIR sensor is the motion detection sensor that detects variation in the IR energy of the environment. It works from 3 to 7 metres of lenght based on the calibration. It has got good accuracy and the sensor is very cheap. It can be used for alive human ditection, automatic door opens and for security alarms.
PIR sensor is a digital sensor which has three pins. vcc, ground and Dout. It can be directly interfaced with arduino. Data out can be connected to any of the digital pins.

Components required

1. Arduino
2. PIR sensor
3. Jumper wires
4. Led 

Step 1 Pin connections

           Vcc - 5v

          Dout- any digital pin

          Pin 13 - Led

Step 2. Dump the below code to arduino

The code is tested for its functionality

Whenever motion is detected by PIR, the LED will turn ON. The glowing interval depends on the calibration of PIR sensor. Before trying, check out the calibration of the sensor.

1. /*
2. * PIR sensor tester
3. */
4. int ledPin = 13; // choose the pin for the LED
5. int inputPin = 9; // choose the input pin (for PIR sensor)
6. int pirState = LOW; // we start, assuming no motion detected
7. int val = 0; // variable for reading the pin status
8. 
   
9. void setup() 
10. {
11. pinMode(ledPin, OUTPUT); // declare LED as output
12. pinMode(inputPin, INPUT); // declare sensor as input
13. Serial.begin(9600);
14. }
15. void loop()
16. {
17. val = digitalRead(inputPin); // read input value
18. if (val == HIGH) // check if the input is HIGH
19. {                   
20.     digitalWrite(ledPin, HIGH);    // turn LED ON
21. if (pirState == LOW) 
22.     {
23.                                 // we have just turned on
24. Serial.println("Motion detected!");
25. // We only want to print on the output change, not state
26. pirState = HIGH;
27. }
28. } 
29. else
30. {
31. digitalWrite(ledPin, LOW); // turn LED OFF
32. if (pirState == HIGH)
33.    {
34. // we have just turned of
35. Serial.println("Motion ended!");
36. // We only want to print on the output change, not state
37. pirState = LOW;
38. }
39. }
40. }