This is an open-source programmable motion detector to switch a voltage when some movement happened. The actual motion sensor is the RCWL0516 which you can get for cheap on Amazon or eBay.
This consists of an ATTiny85 which can be programmed. GPIO2 is detecting if a motion has happened and GPIO1 is triggering the MOSFET. To flash a ATTiny85 you can follow this tutorial: http://highlowtech.org/?p=1695 I am using an Adruino Pro Mini and a TTL USB Stick.
