This project enables you to drive two unipolar stepper motor or eight electric light bulb or DC motors. There are eight DC power switch you can open or close through PC parallel port. For safety reason, digital interface to PC uses optocouplers. You can connect up to six circuits to a single LPT, driving up to twelve step motors or 48 bulb.
The range of circuit power supply should be from 14 to 50V. Circuit can handle 10 A maximum for all switch but if you use IRF540 then the max single switch current is 5A. You can use power supply down to 7 V if you use logic level MOS.
“For highly inductive load, like motors, you should use “fast recovery time” diodes type and capable to sink load peak current. But, If you cannot get high speed diode, better to use slow 1N4001 than none” said VincenzoV, the designer.
Stepper Motor Driver
Download Schematic and PCB (.tgz)