Any Python and Raspberry Pi experts out there?

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peejayw

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#260059 8-Nov-2019 14:39

Any kind Python experts there who could produce some code to turn one GPIO pin on and off multiple times per day, 7 days a week? I need to specify the start and end times ie On at 8am off at 8:02 am for probably 6 time slots per day.

My knowledge of Python is pretty basic but if someone could produce the basic script I could then modify it as required.

I'm supposed to respect my elders, but it's getting harder and harder for me to find one now.

bazzer

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#2350311 8-Nov-2019 17:45

What's your timeframe?
Does it need to be doing anything else at the same time (i.e. what OS does it need running in the background, assuming Raspbian)?
How do you imagine specifying the times (text config file)?

I don't know how to do this, but it doesn't sound that hard so I might be willing to have a crack if no one else can help you out but I don't know when I'd be able to get to it.

afe66

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#2350321 8-Nov-2019 18:07

Look at the raspberry pi foundation education documents on how to use the gpio connectors. There are tutorials from memory which teach you how to light a led so if you could start looking there.

There are lots of basic educational resources out there.

My programming skills ended with bbc basic in 1980s and I was able to write a python script converting entered text into Morse code beeps with beeper connected to gpio and a bread board.

You might surprise yourself in how easy it could be.

1yippy1

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#2350393 8-Nov-2019 18:50

Check this out https://www.raspberrypi.org/forums/viewtopic.php?t=195014

itxtme

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#2350505 8-Nov-2019 23:48

First, make sure you test with a voltage meter. Also make sure your assumptions on GPIO channels match the Pi version you are attempting. Different versions have different locations and you may be looking at the wrong map! Make sure you are using an always off channel.

Your requirement for time frames isnt too clear, but would it not be easier to have two python scripts, one that turns the GPIO on and then one that turns off and have them timed on your cron job?

On (08:00, 10:00, 12:00)

0 8,10,12 * * * /usr/bin/python turnOn.py >/dev/null 2>&1

Off at (08:02,10:02,12:02)

2 8,10,12 * * * /usr/bin/python turnOff.py >/dev/null 2>&1

I dont code in Python, however I believe something along the lines of below would work as a python script (untested). I have used similar in a relay I played with.

Turn on

import RPi.GPIO as GPIO
import time

channel = 21

# GPIO setup
GPIO.setmode(GPIO.BCM)
GPIO.setup(channel, GPIO.OUT)

#Turns GPIO on
def motor_on(pin):
GPIO.output(pin, GPIO.HIGH) # Turn on

if __name__ == '__main__':
try:
motor_on(channel)
except KeyboardInterrupt:
GPIO.cleanup()

Turn Off

import RPi.GPIO as GPIO
import time

channel = 21

# GPIO setup
GPIO.setmode(GPIO.BCM)
GPIO.setup(channel, GPIO.OUT)

#Turns GPIO off
def motor_off(pin):
GPIO.output(pin, GPIO.LOW) # Turn off

if __name__ == '__main__':
try:
motor_off(channel)
GPIO.cleanup()
except KeyboardInterrupt:
GPIO.cleanup()