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I want to ask - Is it possible to run bipolar stepper motor with uln2003 or uln2803 ic?? Answered

I want to ask - Is it possible to run bipolar stepper motor with uln2003 or uln2803 ic??, because l293d ic is very costly here. If yes then can you plz post a schematic here. I have searched over the net and found no useful information about it. plz HELP?




6 years ago

Yes, it is! *
*- It actually depends :) on the size of the motor and whether your application can afford losing some energy (ok, a lot of energy - about 50%). In other words, I would not use it for a battery-powered project but if you have the mains power handy, here is how to drive a small bipolar motor with an Arduino and a ULN2803 (same principals would apply to ULN2003).

Actually that is incorrect, the bipolar motor is fine to use with the ULN2003 it just happens that the most commonly used motor is salvaged from scrap floppy drives, so hobbyists and hackers love them.
If by chance you are using a Bipolar or hybrid motor you do not lose any torque. You are just neglecting to charge the center taps of each coil, generally you will see two coils on Nema 14 - 32 motors and the Nema is usually purchased as a unipolar motor.
Also the bipolar motor is the motor found in the floppy drive of your computer, generally the motors you buy online with 6 or more wires are Hybrid.
Tape the "center tap" wire for each coil and wire the motor as if it where unipolar.

Not quite sure what you mean. To drive a bipolar stepper motor (one without the center tap) properly, you need to be able to energize the windings in both directions. For that you need to alternate between sourcing and sinking current on each of the four available wires. A Darlington array such as ULN2003 (2803) can only sink but not source current. The ULN for bipolar stepper solution I was referring to is more like a hack, not quite a "normal" way of driving a bipolar stepper. 

Also, in response to the original poster, you mention that L293 Half-H drivers are costly in your locale. Check the costs of SN754410 chips - last I was able to source them on eBay for something like $0.33 apiece. It's  functionally analogous to the L293 although takes slightly less current. if you don't need to push for the max current in your application, SN754410 might to just as well.

I didn;t say without one center tap, I said with center taps. Each coil will have one and you don't need to connect them.
You are charging the coil to spin the motor.


6 years ago

If you want to keep the software install simple try http://whatisacnc.com/sprinter/ for windows systems.
Also the center taps don't need to be energized.

No because the field current needs to be reversed - Look closely at the Picaxe URL I sent in answer to your last question which was the total reverse of this question.