stepper motor wiring

bobroan

I am trying to wire the mitsumi stepper motor and uln2003a so my bs2x can operate them.· But I see that the stepper motor needs 12 volts and all my power for the stamp is about 5 volts.· Can I just use a 12 volt wall wart or do I need something different for this power?

Also, what ground do I connect the uln2003A to?· Is it the ground for the basic stamp power or the 12 volt power?· And is the common from the ULN2003A 12 volts or 5 volts?

Finally, did I forget anything else?

thanks

bob

Newzed

You can use a 12 volt wall wart.

The common for the 2003 is 5volts.· All grounds must be tied together.



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Sid Weaver
The Stamp Tester

http://hometown.aol.com/newzed/index.html
·

LoopyByteloose

Uh, I am looking at a Specifcation Sheet for the UNL2803A, and it says it can handle 50Volts at 500ma.

SID - Where did this 5Volts come from? Was that UNL2003A a typo?

It seems to me that the UNL2?03a can really drive a wide range of steppers or other devices.

Also, www.phanderson.com has a tutorial (tutorial #3) on using the Stamp and the UNL2*03a for steppers.

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G. Herzog in Taiwan

Post Edited (Herzog) : 8/23/2004 1:44:34 PM GMT

Jon Williams

There is documentation on our web site that shows how to connect everything.· Usually,· the 5 volt supply for your BASIC Stamp will be derived from the 12 volt supply so the ground will already be common.· If you have separate supplies, then the grounds need to be connected together as Sid indicated above.

Docs: http://www.parallax.com/dl/docs/prod/motors/27964.pdf

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Jon Williams
Applications Engineer, Parallax
Dallas Office

Mark Stevens

Hi,
I'm using the Mitsumi motor and ULN2803A & had some of the same questions that the original post mentioned. For the most part, they've been answered, thanks.

Even though I got my circuit to "work", one thing is still bothering me. I happened to use a 9V battery rather than wall wart since I didn't have one in the right voltage range. I attached the positive lead to the "+12V" connection in the circuit and "guessed" that the negative battery lead should be attached to the GND/Vss. Well, the motor works perfectly, but (as I THINK I recall from college physics), the negative terminal of a seat of EMF is not the same as "ground" (?).

So, my questions are:

1. Since Vss is in-circuit with the battery, doesn't that expose the stamp to possible damaging current (Vss on the BOE is Vss on the Stamp, right?)

2. Whether I'm using battery or wall wart, there is always a "+" and "-" terminal of course, or the current wouldn't be able to flow. Why do virtually all circuit diagrams show where to hook up the "+" and (for dummies like me, anyway) not show where the "-" is connected?

Here's my "working" circuit:

http://www.geocities.com/mark_stevens_32/stepper_circuit.bmp

Any info would be helpful,

Thanks