Arduino + ULN2803 CONTROLLER

[cjgaus]

Hey peeps i wanted to know if anyone had or knew of any schematics for connecting a arduino mega to uln2803 darlington arrays to make a cnc controller.

Cheers

[Drools]

here is a link to a unipolar driver using a uln2803. The author describes how to interface a different clock source, read microcontroller to adjust the speed.
74194 Unipolar Stepper Motor Driver
It is a simple low current circuit. I'm interested it it because he offers boards/kits/assembled units for a very reasonable price.
Schematics are included if you wanted to roll your own.

[CullenNewsom]

Follow the link from the tutorial for the little Arduino to Fritzing. Hooking it up is pretty straightforward.
Arduino - MotorKnob

There is also a nice driver based on the Allegro A3967. It probably isn't suitable for most CNC machines, but is a good example to work from. Easy Driver stepper motor driver

[scriptster]

And it does not have to be only unipolar either. Here is how to drive (small) bipolar stepper with Arduino and ULN2803 (ULN2003) with schematics and the Arduino code. It all depends on your application and how much money you want to spend ...