stepper.py

# my first stepper program
# intention: to test the stepper motor
# Kiat Huang <kiat.huang@gmail.com>
# Created: 20070427
# License: https://choosealicense.com/licenses/apache-2.0/
#
# Based on
# http://www.raspberrypi-spy.co.uk/2012/07/stepper-motor-control-in-python/
#
# My hardware
# 1. Stepper Motor: 28BJY-48
# 2. Stepper Motor Driver Board: ULN2003
#    Bought here: http://www.ebay.fr/itm/292003588929?_trksid=p2057872.m2749.l2649
#    Screenshot (in case the item doesn't exist there any more): http://goo.gl/reIvWL
# . Raspberry Pi B+ v1.2 with 40 pins

# Usage
#
# $0          # clockwise, each step is 0.01 seconds
# $0 500      # clockwise, each step is 0.5  seconds
# $0 500 -1   # counter-clockwise, each step is 0.5 seconds

# Features
#
# 1. Makes the motor spin at a certain speed until user interrupts CTRL-C
# 2. On interrupt, resets the GPIOs to LOW
#

# Notes
# 1. Code working with python3.4 on Rasbian
#    pi@raspberrypi:~ $ uname -a && cat /etc/debian_version
#    Linux raspberrypi 4.4.50+ #970 Mon Feb 20 19:12:50 GMT 2017 armv6l GNU/Linux
#    8.0
# 2. Adapt to your own GPIO pins
# 3. Hardware worked with 3.3V (accidentally) as well as 5V as intended
# 4. Works when the motor spins and the LEDs flash on the board matching Seq

# Import required libraries
import sys
import time
import RPi.GPIO as GPIO

# Define GPIO signals to use
# Physical pins 35, 36, 37, 38
# GPIO19,GPIO16,GPIO26,GPIO20
StepPins = [19,16,26,20]

# Define simple sequence : 4 step seq so 32 x 64 = 2048 steps/rev
Seq1 = [[1,0,0,0],
        [0,1,0,0],
        [0,0,1,0],
        [0,0,0,1]]


# Define advanced sequence : 8 step seq so 64 x 64 = 4096 steps/rev
Seq2 = [[1, 0, 0, 0],
       [1, 1, 0, 0],
       [0, 1, 0, 0],
       [0, 1, 1, 0],
       [0, 0, 1, 0],
       [0, 0, 1, 1],
       [0, 0, 0, 1],
       [1, 0, 0, 1]]


Seq = Seq1
StepCount = len(Seq)

# Read wait time from the command line
if len(sys.argv)>1:
    WaitTime = int(sys.argv[1])/float(1000)
else:
    WaitTime = 10/float(1000)

# Read direction, only if wait time is also set
# Set to 1 or 2 for clockwise
# Set to -1 or -2 for anti-clockwise
if len(sys.argv)>2:
    StepDir = int(sys.argv[2])
else:
    StepDir = 1

# Initialize variables
StepCounter = 0
TotalSteps = 0
# Start main loop
try:
    while True:

        print (StepCounter, Seq[StepCounter])

        # Use BCM GPIO references
        # instead of physical pin numbers
        GPIO.setmode(GPIO.BCM)

        for pin in StepPins:
            print ("Setup Pins")
            GPIO.setup(pin, GPIO.OUT)
            # GPIO.output(pin, False)

        for pin in range(0,4):
            xpin = StepPins[pin] # get GPIO
            if Seq[StepCounter][pin]!=0:
                print ("Enable GPIO ", xpin)
                GPIO.output(xpin, True)
            else:
                GPIO.output(xpin, False)

        StepCounter += StepDir

        # If we reach the end of the sequence, start again
        if (StepCounter >= StepCount):
            StepCounter = 0
        if (StepCounter < 0):
            StepCounter = StepCount + StepDir

        # Count total steps
        TotalSteps += 1

        # Wait before moving on
        time.sleep(WaitTime)


except KeyboardInterrupt:
    GPIO.cleanup()
    print("Total Steps = ", TotalSteps)

except:
    GPIO.cleanup()
    if sys.version_info[0] < 3:
        print ("Must be using Python 3")
        raise