Control Unipolar stepper with BS2 and uln2003

[Jude Teddy]

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]

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.

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Jon Williams
Applications Engineer, Parallax