Raspberry Pi Interface with 28BYJ-48 Stepper Motor

Demonstration

Physical connections

Notes

1. V_CC for the stepper is 5V, so I used an external supply rather than the 5V GPIO pin, since the current is limited on that pin.
2. The output voltage of the GPIO pins is sufficient to drive the controller board without level shifting.
3. Any GPIO pins can be used. I used GPIO13, GPIO16, GPIO26, and GPIO21.

Python code

#!/usr/bin/python
# Terry Sturtevant, May 10, 2017
import RPi.GPIO as GPIO
import time


GPIO.setmode(GPIO.BCM)
stepper_pins=[13,16,26,21]

GPIO.setup(stepper_pins,GPIO.OUT)

stepper_sequence=[]
stepper_sequence.append([GPIO.HIGH, GPIO.LOW, GPIO.LOW,GPIO.LOW])
stepper_sequence.append([GPIO.HIGH, GPIO.HIGH, GPIO.LOW,GPIO.LOW])
stepper_sequence.append([GPIO.LOW, GPIO.HIGH, GPIO.LOW,GPIO.LOW])
stepper_sequence.append([GPIO.LOW, GPIO.HIGH, GPIO.HIGH,GPIO.LOW])
stepper_sequence.append([GPIO.LOW, GPIO.LOW, GPIO.HIGH,GPIO.LOW])
stepper_sequence.append([GPIO.LOW, GPIO.LOW, GPIO.HIGH,GPIO.HIGH])
stepper_sequence.append([GPIO.LOW, GPIO.LOW, GPIO.LOW,GPIO.HIGH])
stepper_sequence.append([GPIO.HIGH, GPIO.LOW, GPIO.LOW,GPIO.HIGH])



try:
	while True:
#		for row in reversed (stepper_sequence):
		for row in stepper_sequence:
			GPIO.output(stepper_pins,row)
			time.sleep(0.01)

except KeyboardInterrupt:
	pass

GPIO.cleanup()
    

Notes

1. To change direction of the motor, change which of the two "for" loop lines to run.
2. This example uses half stepping; if you want full stepping just remove the steps of the sequence which have two HIGH bits at a time.