View Full Version : Control Unipolar stepper with BS2 and uln2003

Jude Teddy
05-06-2006, 04:14 AM
http://forums.parallax.com/images/smilies/cool.gif I have interfaced a BS2 with a ULN2003 which i intend to use in driving a unipolar stepper motor. The uln2003 is setup so it can be driven by two data lines (as in the basic projects example. I have tried every possible code to drive the motor to no avail. It quivers all the time. I am using the "high and Low" statements. eg. high 2, low two, high 3, high 2 etc. Please I need help.

Jon Williams
05-06-2006, 05:15 AM
Assuming you have good code and your ULN2003 connections are correct, you probably have the coils connected incorrectly. Do this:

1. Swap the "outer" coils and retest -- if it works, you're done, otherwise....
2. Swap the "inner" coils (do not change anything done in Step 1). It should work now.

Jon Williams
Applications Engineer, Parallax