Learn about electronic motion detectors with this deluxe kit that includes a highquality enclosure with a mounting bracket. The motion detector makes a loud doorbelllike dingdong sound when it detects motion. The kit is based on a pyroelectric infrared (PIR) sensor which is a unique sensor that you can use to give your projects the ability to react to your presence.

The instructions include several pages of explanation that describe the various parts of the circuit and how the PIR sensor works.