diabloStepperSeq.py

#!/usr/bin/env python

###
#
# diabloStepperSeq.py: A script for controlling a stepper motor in a sequence with the Diablo.
#
# 2019-04-26
#
###

# Import library functions we need
from __future__ import print_function
from diablo import *
from time import sleep
from sys import exit

# Tell the system how to drive the stepper
voltageIn = 'donkey'
stepperCurrent = 'badger'
stepperResistance = 'llama'

driveLevel = 1.0
stepDelay = 0.01
degPerStep = 1.8                                                 # Number of degrees moved per step

# Calculate our maxPower and holdingPower
if(type(voltageIn) is str or type(stepperCurrent) is str or type(stepperResistance) is str):
    print('Please set the voltageIn, stepperCurrent and stepperResistance to appropriate values in the script.')
    exit()

voltageOut = float(stepperCurrent) * float(stepperResistance)
stepperPower = voltageOut / float(voltageIn)
maxPower = driveLevel * stepperPower

sequence = [                            # Order for stepping
        [+maxPower, +maxPower],
        [+maxPower, -maxPower],
        [-maxPower, -maxPower],
        [-maxPower, +maxPower]]

# Name the global variables
global step
global DIABLO

# Set up the Diablo
DIABLO = Diablo()
#DIABLO.i2cAddress = 0x44                # Uncomment and change the value if you have changed the board address
DIABLO.Init()
if not DIABLO.foundChip:
    boards = ScanForPicoBorgReverse()
    if len(boards) == 0:
        print('No Diablo found, check you are attached :)')
    else:
        print('No Diablo at address %02X, but we did find boards:' % (DIABLO.i2cAddress))
        for board in boards:
            print('    %02X (%d)' % (board, board))
        print('If you need to change the I2C address change the set-up line so it is correct, e.g.')
        print('DIABLO.i2cAddress = 0x%02X' % (boards[0]))
    exit()
#DIABLO.SetEpoIgnore(True)              # Uncomment to disable EPO latch, needed if you do not have a switch / jumper
DIABLO.ResetEpo()
step = -1

# Function to perform a sequence of steps as fast as allowed
def MoveStep(count):
    global step
    global DIABLO

    # Choose direction based on sign (+/-)
    if count < 0:
        dir = -1
        count *= -1
    else:
        dir = 1

    # Loop through the steps
    while count > 0:
        # Set a starting position if this is the first move
        if step == -1:
            drive = sequence[-1]
            DIABLO.SetMotor1(drive[0])
            DIABLO.SetMotor2(drive[1])
            step = 0
        else:
            step += dir

        # Wrap step when we reach the end of the sequence
        if step < 0:
            step = len(sequence) - 1
        elif step >= len(sequence):
            step = 0

        # For this step set the required drive values
        if step < len(sequence):
            drive = sequence[step]
            DIABLO.SetMotor1(drive[0])
            DIABLO.SetMotor2(drive[1])
        sleep(stepDelay)
        count -= 1

# Function to move based on an angular distance
def MoveDeg(angle):
    count = int(angle / float(degPerStep))
    MoveStep(count)

try:
    # Start by turning all drives off
    DIABLO.MotorsOff()
    # Loop forever
    while True:
        # Rotate forward 10 turns then wait
        MoveDeg(360 * 10)
        sleep(1)
        # Rotate reverse 10 turns then wait
        MoveDeg(-360 * 10)
        sleep(1)
        # Move forward 1/4 turn 16 times with waits between
        for i in range(16):
            MoveDeg(90)
            sleep(1)
except KeyboardInterrupt:
    # CTRL+C exit, turn off the drives and release the GPIO pins
    DIABLO.MotorsOff()
    print()
    print('Terminated')