Rotation Sensors


We’re currently trying to get our potentiometers working and programmed, but if they don’t work we’d like to have a back-up plan. Can any team recommend rotation sensors that they have used in the past?

Potentiometers are nice and easy for actuator positioning if you can (1) mount them to the final output shaft and (2) the output shaft doesn’t rotate 360 degrees continuously.

If you can’t do that, use an optical encoder. has an encoder FAQ.

This is what we’re using:

It’s a pot that keeps turning. It’s called a Follow-up pot. The resistance goes back to zero after a full turn, but there are no stops so it can turn all the way around. We have it going to analog in 1 and use the AD converter to read it.

Pots are actually the easy and reliable technique.

Shaft encoders are the alternative, but are more troublesome to specify and code.

Team 1625 is using the US Digital MA2. It works well because it is an aboslute analog encoder that is the equivalent to a 10-bit digital. Plugs right into the RC Analog in, and gives 1024 different steps for one rotation so it has enough resolution for almost anyone. Its also pretty cheap too.

Here is the link.

Do Not Eat.

Thanks for all of your responses. We’re going to try and use the follow up pot.

Those look nice. I may have to try one of those next season.