Control dc motor using GPIO.PWM problem

Question

I'm trying to make a small remote controlled car with the raspberry pi and attached two small dc motors to it, using the L239D chip. When testing without the remote control (which is a simple android app) the motors work good and the speed is changing. But when I try with the remote control it doesn't work at all. here is the function that receives the remote control params:

def customSpeed(direction,left, right):
    right = int(right)
    left = int(left)
    if direction == "f":
        GPIO.output(Motor1A, GPIO.HIGH)
        GPIO.output(Motor1B, GPIO.LOW)
        GPIO.output(Motor2A, GPIO.HIGH)
        GPIO.output(Motor2B, GPIO.LOW)
        motorR.ChangeDutyCycle(right)
        motorL.ChangeDutyCycle(left)
        print("Got to forward")
    else:
        GPIO.output(Motor1A, GPIO.LOW)
        GPIO.output(Motor1B, GPIO.HIGH)
        GPIO.output(Motor2A, GPIO.LOW)
        GPIO.output(Motor2B, GPIO.HIGH)
        motorR.ChangeDutyCycle(right)
        motorL.ChangeDutyCycle(left)
        print("Got to back")
    ans = "Going "+ ("Forward" if direction == "f" else "Back") +". Left: "+str(left)+". Right: "+str(right)
    print(ans)

The last print, prints the information correct, and when I try to do this methods "offline" they all work properly, but this function does not. Any thoughts?

EDIT: This are my methods for preparing the motors:

GPIO.setmode(GPIO.BOARD)
Motor1A = 16
Motor1B = 18
Motor1E = 22

Motor2A = 19
Motor2B = 21
Motor2E = 23

GPIO.setup(Motor1A, GPIO.OUT)
GPIO.setup(Motor1B, GPIO.OUT)
GPIO.setup(Motor1E, GPIO.OUT)
GPIO.setup(Motor2A, GPIO.OUT)
GPIO.setup(Motor2B, GPIO.OUT)
GPIO.setup(Motor2E, GPIO.OUT)

motorR = GPIO.PWM(Motor1E,100)
motorL = GPIO.PWM(Motor2E,100)
motorR.start(0)
motorL.start(0)

Is there any problem using the tcp connection with the GPIO at the same time?

Answer 1

Essentially if you are using RPI.gpio lib which it looks like you are, (and written in python too) I used to use this lib but sometimes commands didn't correctly setup the pwm and often caused problems due to system access, essentially I could suggest you use pigpio ( http://abyz.me.uk/rpi/pigpio/) as it is a nice and easily usable lib on python, and it has extensive documentation included with it.

The problem using TCP with RPI.gpio too is that as noted before sometimes the pwm doesn't actually reach the servo/motor where as pigpio uses a listener to make sure that the servo/motor receives a smooth signal.

If you have any questions please yell, hope this sheds some light on your problem.