Steve I'm playing with the EasyDriver v3 from Sparkfun at the moment.
http://www.sparkfun.com/commerce/pro...oducts_id=8368
Features:
- A3967 driver configured for 8-microstep mode
- Compatible with 4, 6, and 8 wire stepper motors
- Adjustable current control from 150mA/phase to 750mA/phase
- Power supply range from 7V to 30V. The higher the voltage, the higher the torque.
As is it seems to work really well and there is some discussion on mistreating it at
http://forum.sparkfun.com/viewtopic.php?t=17169
I've posted a piece on driving it with an Arduino at
http://forum.sparkfun.com/viewtopic.php?t=17243 with some test code I used (the Arduino does not naturally give variable frequency output but by using timer interrupts it can be done).
I've been working tonight at lifting the mode pins from the PCB to allow control over the stepper mode so that I can use the various modes. I've run out of pins on the Arduino so I may end up using either 1/8th step or full step for slewing and ignore the rest.
I've had two different orders from Sparkfun and so far the service has been excellent. I use a number of bit's from them in my dew heater controller.
I need to play some more with the supply voltage and current limiting features of the EasyDriver to see what works well.
Bob