My very strong suggestion is to head over to and=20 look at their stepper drivers. My current favorite is the DRV8825=20 which they charge US $6.79 when purchased in multiples of 5. They=20 cost $8.95 if purchased individually. Six different step resolutions: full-step, half-step, 1/4-step,=20 1/8-step, 1/16-step, and 1/32-step Some links: Documentation: This module comes ready to go. Connect the motor with power supply=20 and give it step & direction pulses. The internal regulated supply=20 is generated within the chip, so you don't need to supply Vdd to the board. It just doesn't get any easier. I'm using this module in all of the little CNC machines that some of=20 my guys have built as well as in retrofit boards for Honeywell=20 motorized dampers. It Just Works! The only mod that I do to is to improve the heatsinking: there is a=20 1/4" square solder pad on the rear of the board where the driver chip=20 is mounted: this square pad is peppered with vias filled with solder=20 so as to improve the power dissipation of the chip. I solder a 1/4"=20 diameter threaded brass spacer 1/4" long to that pad and use the=20 spacer to mount the module to the enclosure. This improves the=20 high-current rating of the module, allowing me to get more than 2=20 Amps per phase. You won't need to do that for your little steppers but I mention it=20 for anyone else who needs just that little bit extra Oomph. dwayne At 02:32 AM 8/12/2015, Andries Tip wrote: >Dear All, > >We have a 12 Volt power supply available. The stepper motor is=20 >available in 3 Volt, 6 Volt or 12 Volt (with nominal currents of=20 >0.22A, 0.11A or 0.055A respectively). We need limit switches on both=20 >ends. We have an FPGA that can program the driver IC with any=20 >settings by SPI or other interface. --=20 Dwayne Reid Trinity Electronics Systems Ltd Edmonton, AB, CANADA (780) 489-3199 voice (780) 487-6397 fax www.trinity-electronics.com Custom Electronics Design and Manufacturing --=20 http://www.piclist.com/techref/piclist PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist .