Motion Detector Cat Fountain

Our cat, Murray, had gotten into the habit of preferring to drink from a slow trickle in the bathroom sink.  This wasn't always convenient for us, so I decided to modify a pet fountain.  After checking out several of them, I went with the Drinkwell Platinum.  It has a carbon filter, adjustable stream, large reservoir, and is pretty quiet.  I didn't see the need to have it run constantly, so I wanted to put a motion detector on it to run only when he came near.

This ws a pretty straight forward project and turned out really well.  Murray loves it.

Step 1 Motion Detector

If the fountain is the body of this project, the passive infared motion detector (PIR) is the brain.  I didn't have to search very long to find the perfect detector.  It was very small and simple to wire into a control board.  I found it at http://www.glolab.com .  The detector itself fit perfectly into a 3/8 inch hole I drilled in the front of the fountain frame.  It took me a little time to figure out the best way to hook it up since it has a dedicated relay out.  It turned out that since I was using a solid state relay to activate the pump, the standard out worked best.

The additional items necessary for this project are a small perfboard, 180 ohm resistor, 7805 voltage regulator, AQH2213 solid state relay, 0.1uF capacitor, 10uF 50V capacitor, 1000uF 25V capacitor, a bridge rectifier, 2 Molex KK connectors (male and female for each), and a 3 pin header.