This circuit was design for my plotting machine. this machine was plotting the drawing at x,y plan. with the help of two stepper motors 12 Volts DC and 200 step in one revolution, but this controller run same motor into 400 steps to get more resolution. Software was written in BASCOM-51 Compiler. This circuit has 4 inputs 2 for motor direction and 2 for run step. Some other controller can control the circuit such as another micro-controller or PC bases software. I used PC based software to control the motors of my plotting machine. to see some of pictures of my plotting machine see at PLOTTER and PLOTTER_2. Eight no of out put are used for two motors, first 4 for motor 1 and remaining for the motor 2. Higher voltages motor can be used as 24 volts by replacing the motors to 24 volts and proper +24 volts supply to handle the motors current.
Driver out put Circuit
Every motor coil pair is fed supply through a current limiting resistor, to protect motor windings.Transistors are already reverse fly back voltage protected. If these transistors are replaced , with other no do care that diodes protected transistors should be used.
Power Supply
DC power supply is required for the fallowing circuit, according to motors current, for this project a 3 Amp power supply will be sufficient with full wave filtration, in the range of 15 to 18 volts.
All files in one zip file which contain all schematics, software in basic, its HEX file, Binary file Download