After collecting a few savaged stepper motors from some old ink jet printers, decided to make a controller to run them.
Looking on-line and then looking at what I had in my parts box, came up with this design using parts I had in hand.
The design works on its own, using the NE555N timer. Makes a simple Unipolar stepper motor tester.
Or you can remove the NE555N and control it using a Micro controller or Parallel port. The parallel port control is for another project to use the free CNC machining software making a CNC router. The two pin control is compatible with the CNC software via the parallel port. Use pin 14 = step, pin 5 = direction on the 7SLS191.
When expanding to control two axises, both axises can share the 74LS139 dual one of four decoder. Which will save one chip.
The MOSFETS I used are 2 AMP IRF710, for higher Amperage just drop in a higher current current model.
Link below to download Eagle file and PDF file
PARTS LIST: