Stepper Motor Controller Based on PIC16F84 Microcontroller

The project illustrates the use of a PIC microcontroller in creating the stepper motor controller by sequencing the steps, along the with TIP120 Darlington pairs for the switching circuitry, and a 4050 hex buffer for logic levels and circuit protection.

The stepper motors used in this project were taken from old hard drives and printers where the parts were sold separately. These motors were particularly unipolar steppers which can be distinguished due to the number of wires coming out. Unipolar has 6 wires coming out including 2 green, 1 white, 1 red, 1 yellow, and 1 blue. There are 2 coils in a 4-phase unipolar motor which are center-tapped and each of phases have a wire. An ohmmeter can be used to distinguish between the phases and center tap if the wire colors are random or if there were only 5 wires.

The stepper motor was tested using a PIC16F628A to find out how fast it could operate. The test also uses a 4MHz crystal since a stepper motor works by pulsing each phase in a certain sequence. The speed of the shaft rotation is determined by the delay between pulses.

Rest of the project