HOW TO – Make a very simple proximity detector

Offlogic writes – “Gadget freaks, model railroaders, roboticists or cat-hosts will love the versatility of the Sharp IS471 infrared proximity detector. It is the size of a transistor, operates over the 4-16 volt range, and can detect objects about 4-9 inches away by reflected IR pulses. The basic implementation requires only the IS471, an IR LED and a 9 volt battery and can be built by most any tinkerer in less than 10 minutes.” – Link.