This is the famous bi-polar stepper motor driver called easydriver. It has microstepping capability.
Each EasyDriver can drive up to about 750mA per phase of a bi-polar stepper motor. It defaults to 8 step microstepping mode. (So if your motor is 200 full steps per revolution, you would get 1600 steps/rev using EasyDriver.)
This setting can be easily overridden by tying the MS1 or MS2 pin to ground. It is a chopper microstepping driver based on the Allegro A3967 driver chip. For the complete specs of the design, read the A3967 datasheet.
It has a variable max current from about 150mA/phase to 750mA/phase. It can take a maximum motor drive voltage of around 30V, and includes on-board 5V regulation, so only one supply is necessary.
For different examples on how to use and arduino code, please click here.
For Brian Schmaltz easy driver detailed project (open source), please click here.
