Stepper motor control circuit

For my stepper motor controller I’m using a CD4050 non inverting buffer, output of the Arduino Uno to input of the CD4050 and the output of the CD4050 to drive a TIP120. The Tip120 will apply the ground to complete the coil circuit on the stepper motor. I will put a 1N4001 diode across each coil. I will have four each circuits driving the motor. The motor I’m using is a 3.6V, 2 amps unipolar. I know the TIP will handle 2 amps, but what amp power supply do I need? The way I’m running the stepper is I turn on one coil at a time. I would think a 3amp supply would be more than enough. Think this will work?
john
Mims,Fl

I hope you find this Useful.
[u]**http://arduiny.com/stepper-motor-drivers/**[/u]

Is there any reason why you are not using an "off the shelf" stepper motor driver and saving yourself all the trouble of making one from discrete components?

Can you provide a link to the specifications for the stepper motor you are using?

...R