I found this circuit in my files. I don’t know where it came from, but
it looks like I photocopied it from somewhere years ago. I have been
told that it came from “The Robot Builder’s Bonanza”, by Gordan McComb.
Anyway, I thought that it should be fairly useful, so I decided to post
it here. The circuit is very simple and inexpensive. This is good thing
because most commercial stepper motor controller ICs are quite
expensive. This circuit is built from standard components and can easily
be adapted to be controlled by a computer. If you use cheap surplus
transistors and stepper motor, the price of the circuit can be kept to
|R1, R2 ,R3, R4||4||1K 1/4W Resistor|
|D1, D2, D3, D4||4||1N4002 Silicon Diode|
|Q1, Q2, Q3, Q4||4||TIP31 NPN Transistor (See Notes)||TIP41, 2N3055|
|U1||1||4070 CMOS XOR Integrated Circuit|
|U2||1||4027 CMOS Flip-Flop|
|MISC||1||Case, Board, Wire, Stepper Motor|
- You should be able to substitute any standard (2N3055, etc.) power transistor for Q1-Q4.
- Every time the STEP line is pulsed, the motor moves one step.
- S1 changes the motors direction.