engine.py

import RPi.GPIO as GPIO
from time import sleep

GPIO.setmode(GPIO.BCM)
class Engine(object):
    """docstring for Engine."""
    def __init__(self, GPIO_AIN1, GPIO_AIN2, GPIO_PWMA, GPIO_STBY, pwmHZ):
        self.GPIO_AIN1  = GPIO_AIN1
        self.GPIO_AIN2  = GPIO_AIN2
        self.GPIO_PWMA  = GPIO_PWMA
        self.GPIO_STBY  = GPIO_STBY

        GPIO.setup(GPIO_AIN1, GPIO.OUT)
        GPIO.setup(GPIO_AIN2, GPIO.OUT)
        GPIO.setup(GPIO_PWMA, GPIO.OUT)
        GPIO.setup(GPIO_STBY, GPIO.OUT)
        
        self.pwmHZ      = pwmHZ
        self.pwm        = GPIO.PWM(GPIO_PWMA,pwmHZ)
        self.engineOn()

    def engineOn(self):
        GPIO.output(self.GPIO_STBY,GPIO.HIGH)
        self.pwm.start(0)
        print("Engine: ON")

    def engineOff(self):
        GPIO.output(self.GPIO_STBY,GPIO.LOW)
        print("Engine: OFF")

    def engineGo(self, axis, btn):
    # Calculates direction and speed of engine considering usage of both pad triggers.
    # The range will be from -1(full back) to 1(full forvard)
    # check if engine is ready to go
        # print(axis, last_axis_used)
        direction = self.engineDirection(axis, btn)
        # print(direction)
        speed = self.engineSpeed(btn)
        # print ("Motor cycle is: ", speed)
        self.pwm.ChangeDutyCycle(speed)

    def engineDirection(self, axis, btn):
        if axis == "z" and btn != -1:
            GPIO.output(self.GPIO_AIN1,GPIO.HIGH)
            return 1
        elif axis == "rz" and btn != -1:
            GPIO.output(self.GPIO_AIN2,GPIO.HIGH)
            return -1
        elif axis == "z" and btn == -1:
            GPIO.output(self.GPIO_AIN1,GPIO.LOW)
            return 0
        elif axis == "rz" and btn == -1:
            GPIO.output(self.GPIO_AIN2,GPIO.LOW)
            return 0
        
    def engineSpeed(self, btn):
        """ Calculates PWM based on triggers level"""
        return (btn + 1)/2 * 100