Bipolar_Stepper_Motor_Class.py

import RPi.GPIO as GPIO
from time import sleep

class Bipolar_Stepper_Motor:
    def __init__(self,step_pin,dir_pin,limit_pin,backlash=0): #initializing some basic stuff to keep track of things
        GPIO.setmode(GPIO.BOARD)
        self.position=0
        self.step_pin=step_pin
        self.dir_pin=dir_pin
        GPIO.setup(self.step_pin,GPIO.OUT)
        GPIO.setup(self.dir_pin,GPIO.OUT)
        self.limit_pin=limit_pin
        self.backlash=backlash
    def move(self,steps,direction,duration):
        if steps==0: #don't do anything!
            return 0
        else:
            interval=duration/(steps*1.0) #divide time into time in between step
        if direction==1: #change int direction to EasyDriver direction input
            GPIO.output(self.dir_pin,0)
        elif direction==-1:
            GPIO.output(self.dir_pin,1)
        else:
            print "Bipolar Stepper Motor class move function got a bad direction value!"
        for step in xrange(steps):#xrange is leaner and meaner for # iterations than range
            GPIO.output(self.step_pin,1)#do a step
            sleep(interval/2.0) #wait half the time
            GPIO.output(self.step_pin,0)#the step is done
            self.position+=direction
            sleep(interval/2.0)#finish sleeping - this is the time between low and high pulse
    def correctBacklash(self,new_dir):
        if new_dir==1:#change int direction to EasyDriver-friendly direction
            GPIO.output(self.dir_pin,0)
        elif new_dir==-1:
            GPIO.output(self.dir_pin,1)
        else:
            print "Bipolar Stepper Motor class correctBacklash function got a bad direction value!"
        for step in range(self.backlash):#do steps, but don't update position - the axis hasn't moved
            GPIO.output(self.step_pin,1)
            sleep(0.00005)
            GPIO.output(self.step_pin,0)
            sleep(0.00005)
        print "Corrected for some axis backlash."