Electronic – Spin two wheels in opposite directions with single DC motor

dc motorwheel

I'm using a simple DC motor and the wheels from a small toy car to build a basic ping pong ball launcher.

I've got one of the wheels rotating clockwise, mounted directly on the motor's spindle, and the other wheel is free running (with 40mm distance between the two outer rims). So it does sort of launch the ball, but because one wheel is not connected to the motor it has a real large side spin.

How would I connect the second wheel to the same motor so that it spins in the opposite direction?

Best Answer

You can connect the two with gears, or, since the ping pong balls are light weight, just find a pair of wheels with a diameter about 40mm greater than your current wheels and let the friction play the role of gear teeth. Four wheels would reduce the load your bearings need to apply to keep the shafts aligned; just put the small wheels in the middle.

Diagram

Alternatively, you could just forgo the second axle altogether, and spin the ball against a static plate. It would have a lot of spin when launched, but that might be useful, especially if you can get backspin on it so it curves upwards in flight.

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