Testing and Cause of Failure for Encoders and Hall Effect sensors

[foobert]

firstly, let me say that i have no actual experience with the first gear, (i dropped out of high school way too long ago for that), but i did buy myself a vex kit to play with and the hardware seems to be pretty much the same. you guys just have a little more of it.

anyway, the problem with polling an encoder on my controller would be that for 2ms out of 18.5ms it's busy in a timing loop generating its pwm outputs. that seems like an excellent opportunity to miss a signal.

conversely, the problem with using an interrupt to catch the signals from the encoder is that if it occurs during the 2ms that the processor is counting cycles to produce the pwm it will cause glitches in the signals to the motors.

overall i'd say, that if your issue is positioning, go with a pot. you do have ten bits of resolution. on the other hand at 17Hz you're likely not going to miss anything.

oh, well, guess i've contributed approximately nothing.

later.