what kind of sensor would i need to use to make a led light up when it sees movment? i am wanting to try and make and interactive LED panel that light up leds where you touch or move near
A PIR motion sensor is used for burglar alarms. RadioCrap had one that could sense a person or a cat at up to 10m away. It had an awful DING DANG square-waves sound. I modified one to make a smooth ding-dong sine-waves sound.
Google for "Sharp IR proximity sensors for robot" these are about $10 and sense when a hand is near, they are used in rest-room hand drying air blowers.
The robot guys use them to stop robots bumping in to things.