encoders? what kind and where from?

[ajlapp]

we're working on setting up our sensor suite for the new bot.......

we've never had encoders on our drivetrain though so i'm wondering what types other people use.

i know some use the optical sensors....has anyone else used something more off the shelf like the ones they sell in our legal electronics manuals?

[Tom Saxton]

Check out these from DigiKey:

http://dkc3.digikey.com/PDF/T041/0996.pdf

The ones in the upper left corner look good: high resolution, low price. We just ordered some for our robot. We picked the 128 counts per revolution units, since we have to put them on the drive wheels. Lower resolution would be fine (maybe even better) if you can put them on the motor shaft before you gear down. For testing we've been using some surplus encoders with lower resolution (32 CPR) and in fact they work well enough to make our robot drive reasonably straight.