geopointer.py

#
# GeoPointer
# V2 2018-07-23
# CADJ
#
# Controls two stepper motors 28BYJ-48 under driver ULN2003
#  and a laser diode to point at geographic coordinates in a wall map
#
# Map details:
#   Blue Marble Next Generation: a true-color Earth dataset including seasonal dynamics from MODIS
#   Image corresponds to the month of August 2004
#   Projection: Geographic Plate Carrée, based on an equal latitude-longitude grid spacing
#   Datum: WGS84
#   Plot: 5000 x 2500 mm, in four vertical strips of 21600 x 43200 pixels
#         [1] 90N, 180W to 90S,  90W
#         [2] 90N,  90W to 90S,   0
#         [3] 90N,   0  to 90S,  90E
#         [4] 90N,  90E to 90S, 180E
#

import RPi.GPIO as GPIO
import time

# SETUP
GPIO.setwarnings(False)
GPIO.setmode(GPIO.BCM)

#  horizontal stepper motor
coilA1pin = 4
coilA2pin = 17
coilB1pin = 23
coilB2pin = 24
#  vertical stepper motor
coilC1pin = 27
coilC2pin = 22
coilD1pin = 5
coilD2pin = 6
#   laser trigger
laserPin = 26

motorDelay = 0.002  # seconds between stepper advancements

# GPIO SETUP
GPIO.setup(coilA1pin, GPIO.OUT)
GPIO.setup(coilA2pin, GPIO.OUT)
GPIO.setup(coilB1pin, GPIO.OUT)
GPIO.setup(coilB2pin, GPIO.OUT)
GPIO.setup(coilC1pin, GPIO.OUT)
GPIO.setup(coilC2pin, GPIO.OUT)
GPIO.setup(coilD1pin, GPIO.OUT)
GPIO.setup(coilD2pin, GPIO.OUT)
GPIO.setup(laserPin, GPIO.OUT)

# sequencing for half-step
stepCount = 8
seq = []
seq.append([1, 0, 0, 0])
seq.append([1, 1, 0, 0])
seq.append([0, 1, 0, 0])
seq.append([0, 1, 1, 0])
seq.append([0, 0, 1, 0])
seq.append([0, 0, 1, 1])
seq.append([0, 0, 0, 1])
seq.append([1, 0, 0, 1])
STEPX = 0  # global to indicate next step in sequence
STEPY = 0


def cleanup():
    GPIO.output(coilA1pin, False)
    GPIO.output(coilA2pin, False)
    GPIO.output(coilB1pin, False)
    GPIO.output(coilB2pin, False)
    GPIO.output(coilC1pin, False)
    GPIO.output(coilC2pin, False)
    GPIO.output(coilD1pin, False)
    GPIO.output(coilD2pin, False)
    GPIO.output(laserPin, False)


def setStepX(s):
    GPIO.output(coilA1pin, seq[s][0])
    GPIO.output(coilA2pin, seq[s][1])
    GPIO.output(coilB1pin, seq[s][2])
    GPIO.output(coilB2pin, seq[s][3])


def setStepY(s):
    GPIO.output(coilC1pin, seq[s][0])
    GPIO.output(coilC2pin, seq[s][1])
    GPIO.output(coilD1pin, seq[s][2])
    GPIO.output(coilD2pin, seq[s][3])


def forwardX1():
    global STEPX
    setStepX(STEPX)
    STEPX += 1
    if STEPX == stepCount:
        STEPX = 0
    time.sleep(motorDelay)


def backwardX1():
    global STEPX
    STEPX -= 1
    if STEPX < 0:
        STEPX = stepCount - 1
    setStepX(STEPX)
    time.sleep(motorDelay)


def forwardY1():
    global STEPY
    setStepY(STEPY)
    STEPY += 1
    if STEPY == stepCount:
        STEPY = 0
    time.sleep(motorDelay)


def backwardY1():
    global STEPY
    STEPY -= 1
    if STEPY < 0:
        STEPY = stepCount - 1
    setStepY(STEPY)
    time.sleep(motorDelay)


def forwardX(steps):
    for i in range(0, steps):
        forwardX1()


def backwardX(steps):
    for i in range(0, steps):
        backwardX1()


def forwardY(steps):
    for i in range(0, steps):
        forwardY1()


def backwardY(steps):
    for i in range(0, steps):
        backwardY1()


def laserOn():
    GPIO.output(laserPin, True)


def laserOff():
    GPIO.output(laserPin, False)


# def coordsToSteps(?) # determina numero de passos dos motores para chegar a uma posicao
# def moveTo(absCoords):
# def move(deltaCoords):
# def laserOn():
# def laserOff():
# def moveSeq(coordList):
# def calibrate():
# def calibrateOrigin():
# def calibrateExtremities():

def main():
    # test section while main() is not written
    while True:
        laserOn()
        steps = input("How many steps forward in X? ")
        if int(steps) == 0:
            break
        forwardX(int(steps))
        steps = input("How many steps backwards in X? ")
        backwardX(int(steps))
        steps = input("How many steps forward in Y? ")
        forwardY(int(steps))
        steps = input("How many steps backwards in Y? ")
        backwardY(int(steps))

    laserOff()
    laserOn()
    laserOff()
    cleanup()
    GPIO.cleanup()


if __name__ == "__main__":
    main()