This hack will allow you to create a motion sensing electrical switch
You can use this to trigger electrical devices from solenoids to motors to cameras.
Step 1: What you will need
Along with basic soldering skills...
You will need a PIR motion sensor mine is from a defunct home alarm.
A small relay, preferably 12V DC coil type.
A transistor NPN type I used a 2N3904
A diode for inductive suppression I used a 1N4001
Stranded wire, Discarded network cable will work in a pinch
12V DC power supply ( Check the requirements of the sensor)