Hi Bojan.
Maciel was faster than me and answered their questions
I will use two 5 phase driver to control the motors. I hope that does not require any other electronic to control it but it only depends of the soundcard output voltage. The driver need a 4.5v pulse to work.
With this approach I expect get 250 microsteps (resolution of 0,0000576º or 0,207 arcsec with a 1/50 harmonic gear) and 2 selectable speeds.
Maciel already modified Soudstepper to use square pulses to control this drivers, now I need expend some time to perform a lot of tests.
I'm using this driver to this project:
http://www.orientalmotor.com/product..._operation.pdf
[]´s
Marcelo