controlling a stepper motor with an easydriver 3 from sparkfun

science_geek

im trying to interface an easydriver 3 from sparkfun found here i have it working with a basic stamp but when i make the connections to a propellor it doesnt do what its supposed to do. it jitters a lot, if anything comes near the motor controller it shakes and jitters the motor very badly. i have tried using optoisolators to isolate the controllers from the prop but nothing is working. i can on rare occasions get it to spin the motor but if i try changing the direction it does nothing. anyone ever use one of these or at least have a part that would work instead of these that works well with the prop. i was looking at the little step u stepper motor controller, will it do a better job for what i want. im using 3 of them to work my homemade cnc mill. any help is much appreciated.

Timmoore

How are you connecting the sparkfun board to the prop? The sparkfun board runs the stepper chip at 5V. The datasheet for that chip gives the logic high as 3.5V min. The prop can't drive that high so if you are connecting the prop pin directly to the step/dir inputs of the easydriver you may have problems.