I was able to find time this week to perfect my ping pong launcher a bit more. I updated the launching wheel, motor mount, I built a ‘ball limiter’, and I found a hopper to use. It’s still needs more work, but it’s a start.

The old motor mount was big and bulky. Although it gave me an adjustment for the pressure on the ball, it wasn’t necessary. The main problem, aside from weight, was that it would move on its own quite often. I made a new motor mount by molding some InstaMorph plastic into something that will clamp the motor in place. I then hotglued the plastic mount to the PVC pipe. Oh, by the way, I’m using the same piece of PVC pipe as I did for the last one. I just ripped the old motor mount off.

For the new and improved wheel I am actually using a K’nex wheel. It has a very wide rim and is very strong. While spinning at full speed the rubber would try to ‘walk off’ the rim, so I just hot glued it to the rim. This wheel works much better than the old!

The ball limiter is pretty simple. I used a servo that I modded for continuous rotation and I attached to it a mason jar canning lid. On the lid I cut out like 1/3 of a 40mm circle. This semi-circle that was cut out is the same diameter as a ping pong ball. In the PVC pipe I cut a slit with my Dremel for the lid to stick into. You can see this in the pictures easily, but, what happens is a ball that is in the tube will touch the lid as it spins around. When the semi-circle opening gets to the ball, the ball will fall in, move with the lid, and be pushed out on the other side of the lid. Not only does it limit the flow of the balls to the launching head, it also forces the balls into it.

I control the servo with a servo testing box that my brother actually built for me. With the box’s potentiometer I can change the speed and direction that the servo rotates.

The last thing I did was find a hopper. I’m using the top part (or bottom part, sending on how you look at it) or a 5gal water jug. You know, those jugs that go into the top of a small water dispenser. It works well because it holds a good amount of balls, it is funnel shaped, and the central hole is the right diameter for a ping pong ball.

So that’s all I got done for it so far. It’s still a work in progress. I need to build a stand for it and I really need to upgrade the motor if I’m serious about it. It really needs a quiet brushless RC motor and an ESC (electronic speed control) to control it. My DC motor is really loud, vibrates a lot, and isn’t ideal. So maybe when I get the funds I’ll by a good motor for it. We’ll see. . . . .