Keep Your Cats Off Counters with a Auto-Trigger Spray Gun

Sometimes, the best Arduino projects are the most ridiculous. Case in point, this motion-detecting squirt gun. The idea is simple: when it detects motion, the spray gun activates. It’s a perfect way to keep cats off counters or away from furniture.

Whether you just want to prank a friend today, or you're looking for a real solution to keep the cats off the counters or regularly mist the plants, Tinkernut has two DIY auto-triggered squirt-bottle hacks that may work for you. One's easy to make, the other's high-tech but more functional.

The first trick, shown in the video above, is an Arduino-powered squirt bottle that also uses a motion detector to fire rapidly every time there's some motion in front of it. If you're trying to keep the cats off the counters, for example, this is the perfect setup to keep in the corner behind the blender so the cats get a quick, harmless spray every time they jump up on it. You'll definitely need some gear for it—the Arduino for one, but also a PIR motion sensor, not to mention the (cleaned and rinsed!) Raid Power Sprayer motorized spray bottle.

The second trick is a little lower tech (shown in the video below) but uses only components you can pick up at the grocery store. It uses a Glade Plug-Ins automatic air freshener for its motion sensor, and the same (cleaned and rinsed!) Raid bottle for its spray motor and mechanism. In this case though, the sensor in the Glade air freshener can only sense shadows, not motion, and there's a delay between how quickly it can fire, so it's not great for training pets, for example, but it is good for misting plants every day when the light changes, for example. Still, it's an easier build.