我們有二種的工作模式

Full-step:
Half-step.

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Example1 :

half step control:

import time
import sys
import RPi.GPIO as GPIO

def step_8 (p):
    
    if p==0:
            GPIO.output(5,0)
            GPIO.output(6,0)
            GPIO.output(12,0)
            GPIO.output(13,0)

    if p==1:
            GPIO.output(5,1)
            GPIO.output(6,0)
            GPIO.output(12,0)
            GPIO.output(13,0)
             
    if p==2:
            GPIO.output(5,1)
            GPIO.output(6,1)
            GPIO.output(12,0)
            GPIO.output(13,0)
             
    if p==3:          
            GPIO.output(5,0)
            GPIO.output(6,1)
            GPIO.output(12,0)
            GPIO.output(13,0)
    if p==4:
            GPIO.output(5,0)
            GPIO.output(6,1)
            GPIO.output(12,1)
            GPIO.output(13,0)
    if p==5:
            GPIO.output(5,0)
            GPIO.output(6,0)
            GPIO.output(12,1)
            GPIO.output(13,0)
    if p==6:
            GPIO.output(5,0)
            GPIO.output(6,0)
            GPIO.output(12,1)
            GPIO.output(13,1)
    if p==7:
            GPIO.output(5,0)
            GPIO.output(6,0)
            GPIO.output(12,0)
            GPIO.output(13,1)
    if p==8:
            GPIO.output(5,1)
            GPIO.output(6,0)
            GPIO.output(12,0)
            GPIO.output(13,1)

def step_4 (p):
    
    if p==0:
            GPIO.output(5,0)
            GPIO.output(6,0)
            GPIO.output(12,0)
            GPIO.output(13,0)

    if p==1:
            GPIO.output(5,1)
            GPIO.output(6,1)
            GPIO.output(12,0)
            GPIO.output(13,0)
             
    if p==2:
            GPIO.output(5,0)
            GPIO.output(6,1)
            GPIO.output(12,1)
            GPIO.output(13,0)
             
    if p==3:          
            GPIO.output(5,0)
            GPIO.output(6,0)
            GPIO.output(12,1)
            GPIO.output(13,1)
    if p==4:
            GPIO.output(5,1)
            GPIO.output(6,0)
            GPIO.output(12,0)
            GPIO.output(13,1)
    
用另一種寫法
def steps_8(value):
    print value
    global pas
    if(value<0):
        for i in range (0,abs(value)):
            step_8(pas)
            time.sleep(0.005)
            pas+=1
            if(pas>=9):
               pas=1;
   
    else:
        for i in range (0,abs(value)):
            step_8(pas)
            time.sleep(0.005)
            if(pas==1):
               pas=9;
            pas-=1
    step_8(0)        
def steps_4(value):
    print value
    global pas
    if(value<0):
        for i in range (0,abs(value)):
            step_4(pas)
            time.sleep(0.005)
            pas+=1
            if(pas>=5):
               pas=1;   
    else:
        for i in range (0,abs(value)):
            step_4(pas)
            time.sleep(0.005)
            if(pas==1):
               pas=5;
            pas-=1
    step_4(0)       

主程式

if __name__ == "__main__":             

     GPIO.setmode(GPIO.BCM)
     GPIO.setwarnings(False)
     GPIO.setup(5, GPIO.OUT)
     GPIO.setup(6, GPIO.OUT)
     GPIO.setup(12, GPIO.OUT)
     GPIO.setup(13, GPIO.OUT)
     
     step_4(0)
     pas=1       
     print len(sys.argv)
     if(len(sys.argv)<2):
       print ("Parameter error")
       print ("Usage: sudo python steeper.py val mode")
       print ("val = step number >0clockwise, <0 anticlockwise ")
       print ("mode = 0: 8 phase   2: 1 phase ")
     else:
       st=int(sys.argv[1])
       if(len(sys.argv)==3 and sys.argv[2]=="1"):
          print("8 phase moving")
          steps_8(st)
       else:
          print("4 phase moving")
          steps_4(st)

測試:
python stepper.py -500 0
   #  500 steps anti clockwise full step mode 
python stepper.py 800 1
   #  800 steps clockwise, half-step mode. 
 #----------------------------------

Example2:

Python: stepper.py

#!/usr/bin/python

# Import required libraries

import sys

import time

import RPi.GPIO as GPIO

# Use BCM GPIO references

# instead of physical pin numbers

GPIO.setmode(GPIO.BCM)

# Define GPIO signals to use

# Physical pins 11,15,16,18

# GPIO17,GPIO22,GPIO23,GPIO24

StepPins = [17,22,23,24]

# Set all pins as output

for pin in StepPins:

  print "Setup pins"

  GPIO.setup(pin,GPIO.OUT)

  GPIO.output(pin, False)

# Define advanced sequence

# as shown in manufacturers datasheet

Seq = [[1,0,0,1],

       [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]]

StepCount = len(Seq)

StepDir = 1 # Set to 1 or 2 for clockwise

            # Set to -1 or -2 for anti-clockwise

# Read wait time from command line

if len(sys.argv)>1:

  WaitTime = int(sys.argv[1])/float(1000)

else:

  WaitTime = 10/float(1000)

# Initialise variables

StepCounter = 0

# Start main loop

while True:

  print StepCounter,

  print Seq[StepCounter]

  for pin in range(0,4):

    xpin=StepPins[pin]# Get GPIO

    if Seq[StepCounter][pin]!=0:

      print " Enable GPIO %i" %(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

  # Wait before moving on

  time.sleep(WaitTime)

python stepper.py 20

測試 20 milliseconds

#--------------------------------------

Example3 : A Python class to move the stepper motor

where-clock/Stepper.py (Source)

#!/usr/bin/env python

# the 28BJY-48 stepper motor with ULN2003 control board.

from time import sleep
import RPi.GPIO as GPIO

class Motor(object):
def __init__(self, pins, mode=3):
"""Initialise the motor object.

pins -- a list of 4 integers referring to the GPIO pins that the IN1, IN2
IN3 and IN4 pins of the ULN2003 board are wired to
mode -- the stepping mode to use:
1: wave drive (not yet implemented)
2: full step drive
3: half step drive (default)

"""
self.P1 = pins[0]
self.P2 = pins[1]
self.P3 = pins[2]
self.P4 = pins[3]
self.mode = mode
self.deg_per_step = 5.625 / 64 # for half-step drive (mode 3)
self.steps_per_rev = int(360 / self.deg_per_step) # 4096
self.step_angle = 0 # Assume the way it is pointing is zero degrees
for p in pins:
GPIO.setup(p, GPIO.OUT)
GPIO.output(p, 0)

def _set_rpm(self, rpm):
"""Set the turn speed in RPM."""
self._rpm = rpm
# T is the amount of time to stop between signals
self._T = (60.0 / rpm) / self.steps_per_rev

# This means you can set "rpm" as if it is an attribute and
# behind the scenes it sets the _T attribute

rpm = property(lambda self: self._rpm, _set_rpm)

def move_to(self, angle):
"""Take the shortest route to a particular angle (degrees)."""
# Make sure there is a 1:1 mapping between angle and stepper angle
target_step_angle = 8 * (int(angle / self.deg_per_step) / 8)
steps = target_step_angle - self.step_angle
steps = (steps % self.steps_per_rev)
if steps > self.steps_per_rev / 2:
steps -= self.steps_per_rev
print "moving " + `steps` + " steps"
if self.mode == 2:
self._move_acw_2(-steps / 8)
else:
self._move_acw_3(-steps / 8)
else:
print "moving " + `steps` + " steps"
if self.mode == 2:
self._move_cw_2(steps / 8)
else:
self._move_cw_3(steps / 8)
self.step_angle = target_step_angle

def __clear(self):
GPIO.output(self.P1, 0)
GPIO.output(self.P2, 0)
GPIO.output(self.P3, 0)
GPIO.output(self.P4, 0)

def _move_acw_2(self, big_steps):
self.__clear()
for i in range(big_steps):
GPIO.output(self.P3, 0)
GPIO.output(self.P1, 1)
sleep(self._T * 2)
GPIO.output(self.P2, 0)
GPIO.output(self.P4, 1)
sleep(self._T * 2)
GPIO.output(self.P1, 0)
GPIO.output(self.P3, 1)
sleep(self._T * 2)
GPIO.output(self.P4, 0)
GPIO.output(self.P2, 1)
sleep(self._T * 2)

def _move_cw_2(self, big_steps):
self.__clear()
for i in range(big_steps):
GPIO.output(self.P4, 0)
GPIO.output(self.P2, 1)
sleep(self._T * 2)
GPIO.output(self.P1, 0)
GPIO.output(self.P3, 1)
sleep(self._T * 2)
GPIO.output(self.P2, 0)
GPIO.output(self.P4, 1)
sleep(self._T * 2)
GPIO.output(self.P3, 0)
GPIO.output(self.P1, 1)
sleep(self._T * 2)

def _move_acw_3(self, big_steps):
self.__clear()
for i in range(big_steps):
GPIO.output(self.P1, 0)
sleep(self._T)
GPIO.output(self.P3, 1)
sleep(self._T)
GPIO.output(self.P4, 0)
sleep(self._T)
GPIO.output(self.P2, 1)
sleep(self._T)
GPIO.output(self.P3, 0)
sleep(self._T)
GPIO.output(self.P1, 1)
sleep(self._T)
GPIO.output(self.P2, 0)
sleep(self._T)
GPIO.output(self.P4, 1)
sleep(self._T)

def _move_cw_3(self, big_steps):
self.__clear()
for i in range(big_steps):
GPIO.output(self.P3, 0)
sleep(self._T)
GPIO.output(self.P1, 1)
sleep(self._T)
GPIO.output(self.P4, 0)
sleep(self._T)
GPIO.output(self.P2, 1)
sleep(self._T)
GPIO.output(self.P1, 0)
sleep(self._T)
GPIO.output(self.P3, 1)
sleep(self._T)
GPIO.output(self.P2, 0)
sleep(self._T)
GPIO.output(self.P4, 1)
sleep(self._T)

if __name__ == "__main__":
GPIO.setmode(GPIO.BOARD)
m = Motor([18,22,24,26])
m.rpm = 5
print "Pause in seconds: " + `m._T`
m.move_to(90)
sleep(1)
m.move_to(0)
sleep(1)
m.mode = 2
m.move_to(90)
sleep(1)
m.move_to(0)
GPIO.cleanup()

the motor round by 90 degrees, pause for 1 second, move it back again

#--------------------------------

28BYJ-48 Stepper Motor with ULN2003 driver and Arduino Uno

5 volts DC => about 15+ RPM
12 volts DC => about 25+ RPM.

28BYJ-48 Stepper Motor 特性

Motor Type	Unipolar stepper motor
Connection Type	5 Wire Connection (to the motor controller)
Voltage	5-12 Volts DC
Frequency	100 Hz
Step mode	Half-step mode recommended (8 step control signal sequence)
Step angle	Half-step mode: 8 step control signal sequence (recommended) 5.625 degrees per step / 64 steps per one revolution of the internal motor shaftFull Step mode: 4 step control signal sequence 11.25 degrees per step / 32 steps per one revolution of the internal motor shaft
Gear ratio	Manufacturer specifies 64:1. Some patient and diligent people on the Arduino forumshave disassembled the gear train of these little motors and determined that the exact gear ratio is in fact 63.68395:1. My observations confirm their findings. These means that in the recommended half-step mode we will have:64 steps per motor rotation x 63.684 gear ratio = 4076 steps per full revolution (approximately).
Wiring to the ULN2003 controller	A (Blue), B (Pink), C (Yellow), D (Orange), E (Red, Mid-Point)
Weight	30g

Model ： 28BYJ-48
Rated voltage ： 5VDC
Number of Phase ： 4
Speed Variation Ratio ： 1/64
Stride Angle ： 5.625° /64
Frequency : 100Hz
DC resistance ： 50Ω±7%(25℃)
Idle In-traction Frequency : > 600Hz
Idle Out-traction Frequency : > 1000Hz
In-traction Torque >34.3mN.m(120Hz)
Self-positioning Torque >34.3mN.m
Friction torque : 600-1200 gf.cm
Pull in torque : 300 gf.cm
Insulated resistance >10MΩ(500V)
Insulated electricity power ：600VAC/1mA/1s
Insulation grade ：A
Rise in Temperature <40K(120Hz)
Noise <35dB(120Hz,No load,10cm)

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參考資料:

https://www.raspberrypi-spy.co.uk/2012/07/stepper-motor-control-in-python/
http://ingeniapp.com/en/stepper-motor-control-with-raspberry-pi/
http://blog.scphillips.com/posts/2012/12/a-python-class-to-move-the-stepper-motor/
http://42bots.com/tutorials/28byj-48-stepper-motor-with-uln2003-driver-and-arduino-uno/