We have a border collie called Budweiser. In case you didn’t know, border collies are herding dogs. As a consequence, they have an almost unlimited supply of energy, and they need to spend that energy throughout the day else they get bored and depressed.
Given that we don’t have sheep around, we need to resort to activities like throwing the ball for Budweiser to fetch. As you can imagine, however, one gets tired of throwing the ball much sooner than the dog gets tired of fetching it.
The solution? An automatic ball thrower where the dog can deposit the ball and wait for it to be thrown.
The first thing I had to build was the mechanism to actually shoot the ball. I figured that the easiest way to do that was with a fast rotating wheel that would press a tennis ball against a lane. I decided to use the engine of my blender to power the wheel, and to use PVC pipes to build the lane where the ball would run. After some calibration to find the perfect height for the lane I managed to get decent power from this mechanism, as you can see in the video below.
The next step was to figure out how to activate the engine only when a ball was deposited. I solve this problem by inserting a pulse switch inside the PVC pipe where the ball travels. Once the ball hits the switch it activates a timer relay, which in turn turns the engine on for 3 seconds.
The final step was to build ramps on the roof so that regardless of where the dog drops the ball, it is funneled to the PVC pipe.
I am still training Budweiser to use the ball thrower by himself, but he is already having fun with it as you can see in the video below.