Control dc motor using GPIO.PWM problem

[jdorfsman]

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:

Code: Select all

    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?

This are my methods for preparing the motors:

Code: Select all

    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?

[joan]

Code snippets are rarely useful in diagnosing problems.

Would it be possible to post all the code (or at least all the relevant code)?

[B.Goode]

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

Not in general. I do all my experimenting over a network using ssh, and have never had any issues with using GPIO connections that could be related to the network.

[jdorfsman]

Code snippets are rarely useful in diagnosing problems.

Would it be possible to post all the code (or at least all the relevant code)?

Yes, here is the github link: https://github.com/c0rrupt3d/RPiCar

[jdorfsman]

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

Not in general. I do all my experimenting over a network using ssh, and have never had any issues with using GPIO connections that could be related to the network.

Then do you have any clue what could be the problem?
I have all the code in github, if you can look at it, it would be great: https://github.com/c0rrupt3d/RPiCar
Thanks!

[B.Goode]

If you and your collaborators have written all that code then you clearly know far more about python and network programming than I do, so I have nothing to add. But I'm surprised you didn't test it during development to see whether it was working.

My own experiments have not been so sophisticated, and did not involve servers or protocol definitions. I simply used a 'game paddle' approach using a cluster of keys such as W A S Z to represent forward, left, right, back.

[jdorfsman]

If you and your collaborators have written all that code then you clearly know far more about python and network programming than I do, so I have nothing to add. But I'm surprised you didn't test it during development to see whether it was working.

My own experiments have not been so sophisticated, and did not involve servers or protocol definitions. I simply used a 'game paddle' approach using a cluster of keys such as W A S Z to represent forward, left, right, back.

That's the problem, we did test it, the function works offline but not when I try to send the same parameters via the network..

[elParaguayo]

Have you tried debugging this by printing out what commands are being received over the network compared with what you're expecting?

[jdorfsman]

Have you tried debugging this by printing out what commands are being received over the network compared with what you're expecting?

Yes, found nothing strange or different.
Even tried to print all the commands and re send them locally and that worked!
:/

[Ravenous]

I notice in your motor controller you have very sinsibly put debug bits like:

Code: Select all

print("Going straigh with speed: "+str(speed))

Is this actually executing? Is the output appearing?

What I'm getting at, is either it isn't being called at all or it is being called but something else is interfering with the motor outputs immediately after that part executes... that might be a clue.