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I am working on my first Raspberry Pi project while following a course for creating a line-following robot. This is the course. I followed all the instructions and connected the pins as it describes but when I run the code on the Raspberry Pi OS it throws an error:

gpiozero.exc.PinPWMUnsupported: PWM is not supported on pin GPIO7 This is the code:

from gpiozero import Robot
from time import sleep

my_robot = Robot(left=(7,8), right=(9,10))

my_robot.forward()
sleep(1)
my_robot.stop()

I tried to search for solutions and checked the official documentation but it hasn't been helpful. How can I fix this?

E_net4
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youHaveAlsoBeenABeginner
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4 Answers4

1

I had the same problem with gpiozero's CamJamKitRobot and Robot classes when trying to run it in a pipenv (same issue may occur with a virtual env, but I have not tried). Running the script outside of the pipenv (therefore just using the system installed pip packages) resolved the issue for me.

Dharman
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Nelson Maine
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1

The likely reason for this error is that the user has installed gpiozero into a virtual environment without installing a pin library. gpiozero's built-in pin interface does not support PWM. You need to install RPi.GPIO to get the normal experience:

pip install gpiozero rpi-gpio

This is mentioned in the docs: https://gpiozero.readthedocs.io/en/stable/faq.html#why-do-i-get-pinfactoryfallback-warnings-when-i-import-gpiozero

ben_nuttall
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After many checks, it resulted that the GPIO pins and the software were ok. The motors were connected to a L289N Driver Motor module, which wasn't getting enough power from the batteries and this was the cause of the error. In case someone has the same or similar hardware connections and faces this issue, check if the L289N module is powered on (it should turn on the red LED that's on the module).

youHaveAlsoBeenABeginner
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I was following the guide on https://www.raspberrypi-spy.co.uk/2018/02/basic-servo-use-with-the-raspberry-pi/ with Micro Servo WS-SG90 and Raspberry Pi 3B+ and used the gpiozero Python library and ran into the same exception. In my case this was caused by running the program as non-root user. Running the program with sudo made the servo turn. The other alternative would be to use PiGPIOFactory with pigpiod which does not require to run the program with elevated privileges.

Vlad
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