Sometimes, pets need to be trained to stay away from certain things. Over at sump.org, his cats needed to be kept out of his room. He used their natural fear of water by creating the waterwall, a motion-sensing device that sprays water. The project is incredibly simple and uses very few components. It is based around an IR intrusion detector and a windshield washer pump. Although that worked well enough, he also hooked it up to his computer via the parallel port so that he could take pictures as the cats (or people) are sprayed. Although the project is old, it shows how few components are really needed to achieve this kind of behavior.

Related: Motion detecting cat toy

[thanks todd]

It’s Independence Day, so if you have pets and planned a trip, chances are you wrangled a pet sitter to keep your pet from starving or dehydrating to death. Next time, consider letting this infinite water dispenser help you instead.

The dispenser is made of a Tupperware tub, a fish tank water filter, a float switch, and a water solenoid valve. It works essentially the same way as any toilet: the solenoid valve lets water into the filter where it is dispensed to the Tupperware container. The float switch is activated when the water in the container reaches a certain level. When the water level drops due to evaporation or thirsty pets, the float switch goes down and triggers the solenoid to let in more water. The whole works are powered by a GFI outlet for safety since this project involved water, electricity and pets.