PIR sensors are used to detect motion from about 20 feet away. This one has an adjustable delay before firing (approx 2-4 seconds) and adjustable sensitivity.
Runs on 5V-12V power (if you need to run it off of 3V you can do that by bypassing the regulator, but that means doing a bit of soldering). Digital signal output is 3.3V high/low. Sensing range is about 7 meters (120 degree cone)
****PIR sensors and the Raspberry Pi 3 sometimes don't get along - if you're having false trigger reports, make sure the PIR Sensor is far away from the Pi 3***