Is the ULN2003 a suitable stepper driver?

[Ari_Porad]

Hi,

This is not strictly printrbot, but...

I am doing a modification to my printer which requires me to drive a NEMA 14 stepper motor. I bought something off ebay like this: , is that a good enough stepper driver to drive a NEMA 14 motor? (Or whatever the Simple comes stock with?)

Thanks,
Ari

[Mooselake]

The ULN2003 is only good for half an amp, so check the current rating on your stepper motor. The Printrboard's drivers are rated at 2A. Real-life performance is less unless you add some heatsinks and cooling. The ULN2003 does not support microstepping; it's a very simple chip that's not a lot more than some driver transistors.

It really depends on what you're planning to do, so perhaps a full-stepping driver board at 0.5A is suitable. Stepper motors come in many different current ratings, adjusting current and voltage to get the same power. RJ can probably explain it better.

If you want to spend about $4.00 instead of $1.32 (the buy-it-now price for that board) you can get either an Allegro A4982 or TI 8825 pololu type driver board from one of the Chinese suppliers, which would probably be better suited. You can use them without a RAMPS or similar if you want to do some breadboarding. There's an example, using a beaglebone, - in this case the grblshield is mostly just a holder and you can get by without it.

Try to read up on stepper motors and drivers; Google is your friend. Gecko drivers are aimed at a higher power (and bigger dollar) market, but their is worth reading.

Good Luck!
Kirk

[REPRAP SQUAD]

I used ULN chips back in the day but mostly for proof of concept. I remember someone telling me a long time ago about stacking ULN chips to get more usable amperage. I might be mistaken but it's at least something to look into.

I also remember a guy that built a Printrbot original plastic using those chip sets. These days Ramps are cheap enough to go that direction. I just saw an sainsmart arduino mega, Ramps board, end stop switches and wiring sell for $38 with shipping included. Watch eBay auctions closely and I could almost guarantee that you could get a complete ramps setup for less than $50.

[he3d]

Saw your link, but I found that I have never seen such 14 step machine, routine isn't that so?

[Mooselake]

Not sure how that's relevant he3d, and it's pretty close to spam. This topic is about drivers, not buying NEMA14s. The original poster already has a motor.

Your site has driver boards, although I could only find an offer for a group of 5, not the q1 the OP would need, so it's too expensive.

Kirk

[REPRAP SQUAD]

He3d spams all over about 2-3 other RepRap based forums that I go onto.