This Instructable will teach you how to make a motorized ping pong ball gun. These ping pong ball guns are a lot of fun to build, but more fun to shoot. I made this as a Christmas present for my son.
UV LED lights are mounted inside the gun to charge glow-in-the-dark ping pong balls for great night time shoot outs. The UV LEDs also add a cool glow to the barrel of the gun as well.
A red laser with a crosshair pattern is mounted on the front of the gun under the barrel.
The gun is powered by two packs of four "AA" batteries so you can use rechargeable batteries and stay green. One pack runs the motors that fire the ping pong balls. The other pack powers the flashlight head on the top front of the gun, the UV LEDs that charge up glow in the dark ping pong balls, and the laser on the bottom front of the gun.
This video shows the ping pong gun in action and then has a walk through of the gun components.
I think this type of project would be a great candidate for 3D printed parts or parts cut with a CNC or laser cutter. It would be great to have those options for this type of project. I think it would help a great deal with accuracy of the individual parts.