stepper motor control and hookup with prop-1

[electricbob]

Newbie needs help.
I bought a stepper motor from All-electronics and I need help with connections and code to Prop-1. Please see pictures:

http://www.bumperbuzz.com/forumPics/forumPics.html

All I want it to do for now is to rotate to a particular position and stop, then when triggered, rotate the opposite direction and stop, then when triggered again, rotate the opposite direction..... you get the idea
1. I dont know how to interface that 6-wire connector to the pins (or OUTs) on the Prop-1
2. For the "triggers", I want to use snap-action switches
3. Is there a code sample out there to get me started.... I also want to try continuous rotation until triggered, then the other direction...etc
4. See the plastic piece on the shaft? It has 22 (or was it 23) "teeth". How can I remove it? If it can't be removed, does that mean it can only drive a belt? And where can I find these supplies to help me "come off of" the shaft to do something useful?

Many thanks.

[JonnyMac]

You cannot connect that motor to the Prop-1 -- well, you can, but you'll blow the ULN right out of the socket.  How do I know this?  Because it says right on the motor that the coil current is 2.4 amps.  Even if that's for all four coils it still works out to 600mA per coil which exceeds the ULN specs.

Look for something that runs at 12 volts with about 250mA or less per coil -- like this one:
-- http://tinyurl.com/9qpmge

[JonnyMac]

There's BS1 (Prop-1 compatible) code in this document (I wrote it a long time ago):
-- http://www.parallax.com/Portals/0/Downloads/docs/prod/motors/Stepper_Motor_27964.pdf

[electricbob]

Thanks for responding.
I've got 2 of these (below), but theres no indication of power or current. Will they work?

http://www.allelectronics.com/make-a-store/item/SMT-90/NMB-PM25L-024-STEPPER-MOTOR/-/1.html

Even so , I was looking for something with enough strength to rotate about 3 pounds. Any ideas? I'll browse "completed projects" Thanks.

[menehune]

According to the pdf datasheet a user posted in the customer comments you should be able to calculate the current for the motor.
I'm not familiar with stepper motors, but in Unipolar mode, the motor requires 0.24A (240mA) per pole. 
Ohms law => E = R * A.  12V/50ohm= current. 
In Bipolar mode, the data sheet lists 24V at 0.6A (600mA) per pole.

I don't think you'll be able to connect the motor directly to the ULN.  You probably will need appropriately rated driver transistors or the driver chip listed in the datasheet.  But I'm not familiar with steppers, so you may be able to use it unloaded.

[JonnyMac]

As Menehune points you the specs suggest you'll be fine in unipolar mode -- which you're forced to use, anyway, due to the ULN output of the Prop-1.  What you need to determine, of course, is which lead does what (mark them when you do).  The common leads will connect to V+, the coils to OUT0 - OUT3.

That said, not sure that little motor is going to rotate thee pounds.  You might need to get stepper controller (e.g., Geko drive) for a bigger stepper.  I used a Prop-1 to controller a stepper driver that moved an enormous stepper motor on my friend's Halloween display in 2007; most stepper drivers need just a direction and step pulse input (TTL signals).