Swerve Encoder and Wiring Questions

[TheHolyHades1]

Originally Posted by cgmv123

Know how many revolutions your wires can handle, keep track in code and quickly turn the module to unwind the wires when needed.

Given the budget and wire winding/unwinding problem, would it make sense to simply limit the motion to 180 degrees, and reverse wheel direction as necessary? The issue I see here is that there will likely be some very jerky motion when crossing over the 180 degree mark, when the wheel direction has to reverse. I believe this has been attempted before, though I'm not sure to what degree of success.

Additionally, I think doing this would allow us to use a cheap potentiometer. I'm just not sure if a cheap potentiometer will be accurate enough for position sensing; I've heard mixed reviews about the linearity and accuracy of cheap pots.

Originally Posted by Gdeaver

We prefer a absolute encoder for steering position.
http://www.digikey.com/product-detai...393-ND/2620662
Easier on the budget.

Thank you for the suggestion. With this, if I'm not mistaken, the encoder will simply modify its output voltage based on the position of the shaft, and the voltage, when mapped between 0 to 360 degrees, will result in a resolution of roughly 0.088 degrees?

Originally Posted by jman4747

You might start here ...

Unfortunately there isn't anything we can do about the budget. However, a couple of the places you pointed do seem to have cheap options, but that probably means they're a little featureless. I'll check them out though, thanks for the suggestions.

[BeardyMentor]

depending on what you need to do, there are some easier ways to hack together an encoder. I probably would not use these hacks on an FRC robot, but for a testing platform, they are fine.

If all you want to do is sense speed, acceptable results can be had with a reflective sensor like this http://www.robotmesh.com/line-tracki...ONYaAgcT8P8HAQ and using some white and black paint on the shaft of the wheel. If you want something with a bit more resolution you can use a pair of hall effect sensors and attach magnets to the rotating object.

[Ether]

Originally Posted by BeardyMentor

If all you want to do is sense speed...

The present discussion is about measuring steering angle.