Mark I suspect your cheap encoder is incompatible with the Blue. The BB Blue is designed to operate with quadrature encoders. The Sparkfun site does not indicate your encoders are quadrature. There's a lot of other gobblygook in their encoder specifications...magnets and sensors etc...but sadly it's missing the word "quadrature".
Here is a link to a simple explaination of quadrature encoders....https://www.dynapar.com/Technology/Encoder_Basics/Quadrature_Encoder/ Note that the quadrature encoder A and B outputs are 90 degrees out of phase. This is critical. Without them being out of phase it is not possible to determine what direction the shaft is being rotated. So find a way to watch both encoder outputs while you slowly turn the encoder in both directions. A dual channel oscilloscope or logic analyzer is best but you might be able to do it with LEDs or two voltmeters. The A and B pulses should never rise or fall at the same time. They need to be 90 degrees out of phase with each other. Get back to me if you have more questions. Clark -- For more options, visit http://beagleboard.org/discuss --- You received this message because you are subscribed to the Google Groups "BeagleBoard" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. To view this discussion on the web visit https://groups.google.com/d/msgid/beagleboard/f5bb49ac-cb31-485c-911c-eb05d6c61236%40googlegroups.com. For more options, visit https://groups.google.com/d/optout.
