I’m having trouble finding optical encoders for a swerve drive. The best i could find is McMaster’s encoders which are pretty pricey. Anyone know where I could find some good encoders?
AndyMark has some cheapy encoders (http://store.andymark.biz/am-0174.html). They’re kind-of annoying because you’re suppose to superglue them to the drive shaft, but they work.
Newark has a ton of less specialized encoders. They run $5-10. Just go to their site and search “encoder” then click on absolute/mechanical. www.newark.com
Jameco also has half of a dozen choices from $3-20. Try the same search at: http://www.jameco.com.
I also tried digi-key, but they seem to only sell the components if you wanted to build your own.
Thanks a lot. Yea I saw the Andy mark one but wondered how it was suppose to be mounted to the shaft.
You’re welcome! I think you’ll find your best fit at Newark, they seem to have the most thorough selection.
I’m glad to see you’re using encoders for the swerve drive. Lots less to worry about than potentiomers. The only thing is you might want to search for an absolute encoder so the robot can figure out the orientation of the wheels. Usually that means that it’s a triple encoder instead of a double; the third disk will have one notch in it to mark each revolution. That notch always occurs at the same angle so you can use that to initalize your wheels to a certain angle every time your robot turns on.
You might want to consider these at US Digital.
If you go with these, I think there is a connector assembly that you might want to purchase as well.
Or, try these. The price is right, not ball bearing but if you are using them at wheel speed, they’ll last as long as needed.
Here’s the link to a CD discussion.
http://www.chiefdelphi.com/forums/showthread.php?t=70603&highlight=cheap+encoders
Good luck.
Forgot the last link.
http://www.chiefdelphi.com/forums/showthread.php?t=70603&highlight=cheap+encoders
More info on absolute encoders in this thread.
–Ryan
We are very happy with the US Digital S4 encoders (so far). Due to a poor design (initially), we bent the shafts of two of them. They continued to function fine (although with some more friction). Compared to other encoders that we’ve used that have stopped working if we looked at them wrong, we’re very happy. They are very compact and fit in places where other encoders wouldn’t have.
I do strongly recommend getting a cable assembly, CA-MIC4-SH-NC.
The US Digital encoders sold by AndyMark clamp onto a .25" shaft quite well without the need for glue.
We have started using this really affordable encoder ($5).
After testing with the cRio, this Oak/Grigsby Encoder performs at the level of the Grayhill 61R
We mounted the encoder on the CIM with latex tubing connecting the drive shaft.
http://picasaweb.google.com/LamarRobotics/HoustonScrimage#5303645261834041890
For more pictures of the mounting scheme, check out our photo gallery,
http://2009.discobots.org/node/34