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
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)
Step 2: Test the sensor
If this is a used or surplus device you should check the operation before using.
Remove the top cover and examine your sensor.
My sensor uses a 12 V DC supply for operation. The power terminals of the device should show the proper voltage and connection. I used this power requirement to select a relay that was also triggered with 12 V DC.
Connect power, wait for the light to go off then test for motion activation using your hand. The light should go on, stay on for a short time, then off again once the motion stops.
This model worked but the relay connection next to the power connection would not activate so a second method will be needed.