GPIO with Python

antares

Hello !

I'm sorry for my bad English, i'm French and i speak very bad in English.

I have an Orange Pi Zero and i would like to turn it into a connected object (IOT). I am therfore looking to drive a relays, read DHT22 probes, as well as communicate on the I2C bus and communicate with an MQTT broker.

To date, i manage to fly the map relays, communicate in mqtt with paho.mqtt, i realized a program that retrieves messages and runs different threads for my relays (tempo, etc...)

i'm having a problem with the GPIO port, i'm using OPi.GPIO for Python

https://opi-gpio.readthedocs.io/en/latest/api-documentation.html

1. import OPi.GPIO as GPIO
   
2. import time
   
3. GPIO.setmode(GPIO.BOARD)
   
4. GPIO.setwarnings(False)
   
5. 
   
6. pin = 10
   
7. GPIO.setup (pin, GPIO.OUT, initial=GPIO.HIGH)
   
8. 
   
9. try:
   
10. While True:
    
11.   print("High")
    
12.   GPIO.output(pin, GPIO.HIGH)
    
13.   time.sleep(1)
    
14.   print("Low")
    
15.   GPIO.output(pin, GPIO.LOW)
    
16.   time.sleep(1)
    
17. 
    
18. Except KeyboardInterrupt:
    
19. print("Exit")
    
20. exit()

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the program working and i press CTRL + C for exit and i watch in /sys/class/gpio

1. ls /sys/class/gpio
   
2. export gpio199 gpiochip0 gpiochip352 unexport

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the pin number 10 is PG07 in setmode BOARd (7-1)*32+7= 199 so gpio199 is my export.

If i comment the line #GPIO.setup (pin, GPIO.OUT, initial=GPIO.HIGH) in my program and i run it
i have a run time error Channel 10 is not configured.

Whereas the export has alreday been done, if i export my gpio into the /etc/rc.local for exportation on starting the pi.
My result is the same

Also, the parameter initial=GPIO.HIGH or GPIO.LOW not working. My gpio is always with a lower level = 3.3V and higher level = 0V
My relay card is higer level trigger so i'm contrain to used a GPIO.LOW for working relay and used GPIO.HIGH for shutdown.

1. sudo nano /sys/class/gpio/gpio199/active_low

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always contains 0 regardless of the initial setting (GPIO.LOW or GPIO.HIGH).

if i make

1. echo 1 > /sys/class/gpio/gpio199/active_low
   
2. echo 0 > /sys/class/gpio/gpio199/value (relay off)
   
3. echo 1 > /sys/class/gpio/gpio199/value (relay on)

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it's work outside the program.
i don't understand.
thanks for help.
I'm sorry for my english

charlesborough

This is a GPIO interface board with a Python library. It has a Raspberry Pi B+ pinout, a 40-pin header with 0.1” spacing, and a 40-pin male header. The board also has a power and ground bus, 2x2 M2.5 screws, and 4x4 M2.5 screws. pay someone to take my online class

authorscrewuk

This book is for anyone who wants to get started with the Raspberry Pi GPIO ghostwriting service and Python. With the help of this book, you will learn how to use the GPIO with Python in your projects.

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emmaorabelle

This is a Python library-equipped GPIO interface board. It features a 40-pin male header, a 40-pin header with 0.1" spacing, and a Raspberry build now gg Pi B+ pinout. In addition, the board features four by four M2.5 screws, two by two M2.5 screws, and a power and ground bus.