Parts -
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
Notes
1. You should be able to substitute any standard (2N3055, etc.) power transistor for Q1-Q4.
2. Every time the STEP line is pulsed, the motor moves one step.
3. S1 changes the motors direction.
