Sensor help

We have a sports training product under development and need help with the electronic part. The idea is to have a sensor that detects when a person is within 2 to 3 feet and then send a signal to a small electric motor. Is there a sensor on the market that would do this or that we could modify fairly easily???

Thanks for any help

Scott

A PING **broken link removed**

Or this it's cheaper Sharp GP2D12 IR Sensor - 30" / Analog Hobby Engineering: Sensors Section

Hey, you can make it from junk..
an Ir Led and an Ir detector
coupled with a Monostable multi vibrator using 555

Yes, I agree with magnatro that you can make it with two infrared LEDs, one is emitting infrared and another is receiving the reflected ray. If a person is near the receiving one, its receiving signal will intensify significant so that you can easily get a trigger to moter with comparing the receiving signal to a constant voltage. Also you can adjust the constant voltage to get a appropriate detecting distance.

I have once made such a detector with RP222( 2Ir LED) and a single chip, and it can detect an object within one feet. It could work stable.