How Can I Motorize My DIY Prize Wheel?

[toresn]

I've made myself a prize wheel consisting of the following parts:

- Main wheel: Galvanized sheet metal plate (d=250 mm), with a fidget spinner glued on the back. Loosely attached to an M8 threaded axle.
- Logo wheel: Galvanized sheet metal plate (d=90 mm), with a M8 nut glued on the back. Attached to the same M8 threaded axle.

See video here:


This works nicely. However, instead of having to spin the wheel myself I thought it might be fun to have a DC motor handling this. The only problem is I don't know how.

I'd like the wheel to function in the same manner as the one I've already made. That is:

- The main wheel should get going when I press a NO (normally open) switch.
- It should keep on spinning after the switch is released (engine stops).
- The logo wheel should stay static.

I'm going to make another base for the wheel, with a flapper that will slow the wheel down and indicate the winning number. I have access to a sheet metal workshop, so I plan on building it using galvanized metal once I get an idea on how this thing should be designed.

Any help is greatly appreciated!

 

[berkeman]

Welcome to the PF.

I didn't understand your distinction between the Main Wheel and the Logo Wheel, but that doesn't really affect my suggestion.

I think the easiest way to do a pretty effective motorized spin-up mechanism for this would be to use a small 12V DC motor (powered by a "wall wart" transformer from the wall outlet) that couples to the wheel(s) via a rubber drive wheel. When you press down on the actuating lever, that tilts the rubber motor drive wheel against the outside surface of the wheel (at the outer edge) to make mechanical contact, and also closes an electrical switch that provides the 12V power to the motor. When you are happy with the big wheel's spinning speed, you release pressure on the motor lever, which releases contact between the motor's rubber drive wheel and the outer circumference edge of the metal wheel, and turns off power to the motor.

Could that work? It's pretty easy to prototype to see if you are happy with it.

 

[CWatters]

It might be possible to use eddy currents. Eg mount a copper disc on the back of the wheel. Then use a DC motor to spin a magnet in close proximity to the copper. Eddy currents should cause the wheel to accelerate in the same direction. When you switch the motor off the magnet and wheel will continue to spin for awhile due to inertia. If you wanted to slow it down faster you could short out the motor rather than just switch it off. I think this should work but I've never built it.