stepper motor with Arduino + H-Bridge + 10K Pot: how does it work?

I have connected the stepper directly to the Arduino. Now, It was working for a while; but I am not sure if it was the correct operation. And then stopped after a while. I am using the setup as below:

http://arduino.cc/en/uploads/Tutorial/bipolarKnob_schlg.png

http://arduino.cc/en/uploads/Tutorial/bipolarKnob_bblg.png

I then re-powered the board and then started playing with the potentiometer; and it seems like the motor started working again. Could you tell me what the issue may be?

Thanks.

well most probably(without seeing your code etc!) the 10k pot is used to set the intensity of the motor driver driving the motors using PWM thats analogWrite(); so when you open the 10k pot more then the speed gets more and when you close it the speed gets lowered.

Hello,

I was reading through the forum and realized this post.
I had a setup very similar to this gentleman’s but I wanted to remove the pot! how do i make the stepper move then (without having to use analogread())?
Also, If I add two more steppers (making them three) and two more H-Bridges, and an external power supply (12VDC, 3A) how would this work now?
this is how I have connected them all (sorry in advance for the confusing background and too many wires!):

image (17).jpeg