Hiya all, FTI, in stepper motors, have scanned the whole article from Silicon Chip Mag. May 2002. There will be more modern ones avail. Check in S.C.
Gives most of the basics anyway. L.
ps. I hope the res. is O.K.
pps. Asimov, you may need a smaller step motor. ie; 0.9 deg.
Would a 0.9 deg/step motor still run ok off this controller? The guy that built it said he had to swap out the 100K variable resistor for a higher valued one to get the motor to rotate at 1 RPM. I'm gathering if I use a 0.9 stepper, I may have to replace the resistor with the original 100K? I'm also gathering a 0.9 stepper will take smaller steps. Is this correct L? Thanks for the scanned article BTW.
John, No prob. Ahh...have a closer look at the circuit diagram & you'll see VR1 in the lower left of the pic. This pot is used to adjust the speed to whatever is req'd. Yes the 0.9 is a smaller step. It's just a suggestion, in case the 1.8 deg is too great a step. L.
any chance this USB controller may work for this application. It is the one David has mentioned in his thread on motorising his 10" dob. http://www.ar.com.au/~softmark/page44.html
L.
Yes the 0.9 is a smaller step. It's just a suggestion, in case the 1.8 deg is too great a step. 
