For your security needs, this is a very simple little passive infrared motion sensor. It runs on 12 volts; all you do is turn it on, let it stabilize for a few seconds, and then any "warm" movement after that will take the open-collector output pin low. Our friends at Sparkfun report that it operates down to 3.3 volts if you jumper across the on-board regulator. At that voltage, it draws 1.6 mA.
You'll need a pullup resistor on the output pin, and since it's OC, you can "wire-or" a batch of these together and sense them with a single Arduino (or whatever) digital input pin.
There is a minimal PDF Datasheet here. These are very easy to use, and make excellent security sensors for enclosed spaces like boat cabins and labs.
This product was added to our catalog on Wednesday 06 May, 2009.
