Advice on stepper motor

Could some1 with some acknowledgment of these stepper motor give me some advice of what kind I should order, should I go for unipolar or bipolar?

I do know that for a unipolar I need to get a Darlington Transistor Array and for a bipolar I need some H-bridges.

What do you think of this one? http://www.aliexpress.com/product-gs/517614158-NEMA17-78-Oz-in-CNC-stepper-motor-stepping-motor-1-8A-wholesalers.html

or this http://www.aliexpress.com/product-fm/518917089-DC-Gear-Stepper-Step-Motor-with-ULN2003-Driver-Board-5V-4-Phase-28YBJ-48-090055-wholesalers.html

OBS! This is for a laserharp ofcourse

Edit: I dont know if its allowed to post links, if its not please tell me

Thanks,

I have been recently doing the same research, and I can highly recommend the A3977 chip from Allegro. It gives you very smooth control of the stepper, and relatively simple to setup. If you get it, and need help, let me know and i'll send you my wiring diagram.

Thank you,

Did you just get the chip itself (what was the price?) ? And what about the motor, which one did you get?

Yes, I just bought the chip, it was around $4.50. You will also need an adapter if you are breadboarding. The chip is available in two packages, so get the appropriate adapter.

As for the motor, I am modifying another product, so I was stuck with what was in it. It is a 12v, 0.75A, 400 step, 6 wire motor. Being that it is 6 wire, it can be used as a unipolar or bipolar motor.

Okey, I see.

Well Im going to order the stepper motor that is in the upper link, it has 4 wires. Which means that it is either bipolar or unipolar, it doesnt really say which type it is.
But the chip, it is for both of em, correct?

No, the chip only works for bipolar.

The upper link says that it is a hybrid, so presumably it can do both. The one on the lower link comes with a ULN2003, so that is unipolar.

Oh I see

Well you know the lower one, do you think its a weak one compared to the upper one?

I'll review the specs when's get home.

What are you doing, though? What is the motor for?

Mr_Faineant, are you sure, that the NEMA17 (upper link) is unipolar?

I'm not an expert, but I've been a little bit in stepper topics the past month and I once read, that the NEMA17 is a bipolar stepper motor. I'm also not sure, if NEMA17 is a standard, so every NEMA17 motor is bipolar. But I guess, it is. So I rather would say, that the upper link is a bipolar motor.

EDIT: Alright, I just did some little research and it seems to be unipolar/bipolar. Here the source: http://www.watterott.com/de/Schrittmotor-Unipolar/Bipolar-200-Steps/Rev-42x48mm-40V-1200mA-NEMA-17 (the description is in english)

I didn't say that the upper link was unipolar, I said that it was a hybrid. I said that I thought that the lower link was unipolar.

Once again, thanks for replies, really appreciated!

This stepper motor is for a laserharp, as Ive already made one, but now I want to make a frameless with much more beams this is good for me. And as Im playing with the stepper motor, I hope Ill learn in the future to build my CNC.

This is my first year in the univeristy, and I really love what Im Learning over there. This is a new World for me I must say!

Ive ordered the top step motor, waiting for it to arrive :D

I also need to order the A3977 chip, but could you tell me why I should order it? What is the difference between this one and Darlington transistor Array and H-bridge. Beause maybe I am able to get the H-bridge from school.

However is this the correct one? http://www.ebay.com/itm/A3977-A3977SEDT-A3977SEDTR-A3977SEDTR-T-Motor-Driver-/120732834243?pt=LH_DefaultDomain_0&hash=item1c1c3cd9c3

Cheers!

The darlington array (for a unipolar) or h-bridge (for a bipolar) will work just fine for basic functionality, the A3977 just gives you much smoother operation, as it can do 1/8 micro stepping. You can decide of this is necessary depending on your application.

I have only recently started my electrical engineering classes also, and have begun working in lab, and am just as excited to you to see this whole new world opening up before me. It really is amazing. I have begun to think of small projects for this that I can make to simplify menial tasks around the house. It feels good to be able to harness science and exploit it for my benefit. I have a LOT to learn, but that is an exciting prospect to me.

Keep me posted on your progress, and please share any cool tips and tricks that you learn.