This instructable will teach you how to use a PIR sensors with the arduino, and we wil build a simple motion detector!
Step 1: Supplies
1 arduino (with protoshield to make life easy)
1 LED of any color
1 PIR sensor from Parallax (you can find these at most radio shacks)
Solid wire to hook it up
Step 2: Setup
Hook the + to 5v, - to ground and out to pin 7
The take the LED and put power to pin 8 and ground to ground.
If its confusing, take a look at the pictures!