...Driver chip?
It's a PBL3775, I found this http://blog.lampugnani.org/?p=261, but...it's in Italian...
I just got it from a scanner.
Thanks
~ReCreate
Hi ReCreate,
in the datasheet Grumpy_Mike linked figure 7
Half stepping system where PBD 3517/1 is used as controller circuit...
gives you the way to wire the thing up. Just 'replace' the PBD 3517/1 with an Arduino. Apart from +5V and ground you need 4 digital pins with 10K ohm pullup resistors.
Figure 15
Stepping modes.
explains in what order to drive the pins.
I made a small sketch the way described in http://www.arduino.cc/cgi-bin/yabb2/YaBB.pl?num=1212576033/0
Make very sure you trace the right pins to connect to arduino as the driver board has mains/higher voltages than arduinop can swallow.
I check the recycle-shop once a week for old scanners/printers as they tend to have larger components. I got my stepper motor + driver board from a HP SCSI scanner.
Hope this helps,
Jeroen
What? Do you mean that all that this is is a programmed chip that moves the motor? That sucks. 
Do you mean that all that this is is a programmed chip that moves the motor?
No the motor is still under the control of the arduino responding to direction and step signals. It is just that this chip works out what power and polarity to apply to the coils.
Ok then....How can i use it?
Also, Do I need 10 K ohm? The one I have that matches the most is 20K.
How can i use it?
Look at the data sheet page 5 figure 6. This shows how you can wire it up. You will need software to drive the pins in the right sequence.
If you don't want to do that then Figure 7 shows and extra chip PBD 3517/1 this is used as controller circuit in order to provide the chip with the right sequences. In this case you simply feed this with step and direction pulses from the arduino.
Where is the 10K resistor you are worrying about?
2 20k Ohm resistors in parallel = 10k Ohms :).
Putting them in parallel splits the resistance?
Putting them in parallel splits the resistance?
Correct. When putting them in series, just add up the values.
Capacitors are the opposite though, for more capacitance, you need to put them in Parallel, and to split it in half, put them in series.
Woah I never knew that. 
I always though putting resistors in parallel would keep the resistance the same...
though putting resistors in parallel would keep the resistance the same.
No it keeps the current the same.
So if the voltage is the same then the resistance HAS to be lower to satisfy ohms law.