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 under $10.
Note:
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.
List Componet
R1, R2 ,R3, R4_____ 1K 1/4W Resistor
D1, D2, D3, D4_____ 1N4002 Silicon Diode
Q1, Q2, Q3, Q4_____TIP31 NPN Transistor (See Notes) TIP41, 2N3055
U1_____________4070 CMOS XOR Integrated Circuit
U2_____________ 4027 CMOS Flip-Flop
S1_____________ SPDT Switch
MISC 1 Case, Board, Wire, Stepper Motor
Pin & feature IC 4070 CMOS XOR I
Wide supply voltage range: 3.0V to 15V
High noise immunity: 0.45 VDD (typ.)
Low power TTL compatibility: Fan out of 2 driving 74L or 1 driving 74LS
Low power: 50 nW (typ.)
Medium speed operation: 12 MHz (typ.) with 10V supply
Pin & feature 4070 CMOS XOR
Wide supply voltage range 3.0V to 15V
High noise immunity 0.45 VDD typ.
Low power TTL Fan out of 2 driving 74L compatibility or 1 driving 74LS
