Cool Uses For Johnson's

[GregTheGreat]

I was inspired to post this question by a thread from a few months ago discussing the cool uses of servos.

I was wondering what some of your teams have done with the small Johnson motors (I know they were in the 2002 kit)? Has any one used them in a unique way? If so, how?

Thanks,

-Greg The Great

[KenWittlief]

yes! a motor is also a generator and it will put out a DC voltage proportional to its speed.

On the Xcats in 2002, we had a spinning wheel shooter for the soccer balls - we intended to be able to hit the goal from up to 20 feet away, which means we needed precise control of the spinning wheel speed

we put a small plastic wheel on the johnson motor and let it ride against the wheel.

For testing we monitored the output voltage on an oscilloscope. It was our intention to filter the signal, and feed it to one of the analog inputs on the R/C - to close the loop on wheel speed

but we did not have enough time to complete that feature.

But from what we saw on the scope, it would have worked.