I've browsed the web for a while and found several examples/Schematics to control a bipolar stepper motor, but they're all based on components like the L293 H bridge.
This chip won't deliver more than 600 mA, which looks a bit weak if I look at the specs.
Also, my understanding is that 3.0v is the voltage when the motor is stopped, but it could be much higher when it's rotating.
My questions:
-What would you recommend to control this motor? Do I need to use some expensive, high current chip, or a L293 based solution (preferably with no piggyback) would work?
Any examples/schematics you could point me to? (if possible, not a 300$ driver card :-))
-What would be the correct voltage to power the motor?
An LN293 is not suitable for this motor, because it reaches its maximum current at such a low voltage. This sort of motor requires a regulating (or chopping) driver that not only controls the sequence but also the current. You can set the current to be anything you want it to be and there is no need to run the motor at it's maximum current.
Grumpy_Mike:
An LN293 is not suitable for this motor, because it reaches its maximum current at such a low voltage. This sort of motor requires a regulating (or chopping) driver that not only controls the sequence but also the current. You can set the current to be anything you want it to be and there is no need to run the motor at it's maximum current.
Here's an example as Mike describes, or if you can handle sticking to 2A you can try this less expensive driver at Pololu. Both drivers use the same step/direction/enable interface.
If you read the documentation for these drivers you can see that the controller's voltage (5V) is independent of the voltage the motor is running at and you will want to use a higher motor voltage (typically 12V to 40V) to gain more speed with the stepper. If the motor gets too hot to press a finger on it then you need to lower the amperage.