The BEAM Circuits Collection is a BEAM Reference Library site.
Wilf's Nu-based stepper motor drive
Wilf Rigter came up with a nifty (single-IC!) circuit to drive the bipolar stepper motor that's a part of floppy drives:
I've reproduced Wilf's own description of this circuit from here:
I'll be updating this page as I (get time to...) experiment with Wilf's circuit over the coming months.
Warning -- circuit under development; material that follows may not be fully accurate!
Here's a different layout of the NuStepper circuit diagram, with traces and other components overlaid on the 74AC86 chip diagram:
The four boxes in the lower right corner (Yl / Bk / Or / Bn) represent the pins on the stepper motor plug, and the corresponding colors of the stepper motor's wires.
Here's how to lay out the components on a NuStepper PCB (this image is 4 times the size of the actual PCB since this is a fairly small board):
The values for C and R2 determine the neuron firing times
When I build up this card, the 74*86 IC is "socketed," both to protect the IC during soldering, and to allow for experimentation with IC subfamily. Similarly, the timing resistors and timing capacitors are plugged into individual sockets to allow for tinkering with circuit timing (i.e., motor rotation speed).