GPIO as trigger.

[Kimovitzh]

Hi.

So i've got this op and running:

Code: Select all

import RPi.GPIO as GPIO
GPIO.setwarnings(False)
GPIO.setmode(GPIO.BOARD)
GPIO.setup(16, GPIO.OUT)
GPIO.output(16, 1)

And instead of it just turning on, i want it to just give a puls so it can trigger an input on my already existing homeautomation system. So just on and then off again.

Any thoughts?

Regards.
Kim.

[elParaguayo]

At the most basic

Code: Select all

switch on
sleep
switch off

How long a pulse do you need? How accurate does it need to be?

I think the pigpio module has a trigger function that may also suit your needs: http://abyz.co.uk/rpi/pigpio/python.html#gpio_trigger

[Laurens-wuyts]

you could do something like this:

Code: Select all

import RPi.GPIO as GPIO
from time import sleep

GPIO.setmode(GPIO.BOARD)
GPIO.setup(16, GPIO.OUT)
GPIO.output(16, 1)
sleep(0.1)
GPIO.output(16,0)
GPIO.cleanup()

After you used the GPIO pins and your program is done, you need to run "GPIO.cleanup()" so you don't get error messages.

Laurens

[Kimovitzh]

At the most basic

Code: Select all

switch on
sleep
switch off

How long a pulse do you need? How accurate does it need to be?

I think the pigpio module has a trigger function that may also suit your needs: http://abyz.co.uk/rpi/pigpio/python.html#gpio_trigger

I think the time on this is ok, but if i want to set up the time, how do i do then?

[Kimovitzh]

you could do something like this:

Code: Select all

import RPi.GPIO as GPIO
from time import sleep

GPIO.setmode(GPIO.BOARD)
GPIO.setup(16, GPIO.OUT)
GPIO.output(16, 1)
sleep(0.1)
GPIO.output(16,0)
GPIO.cleanup()

After you used the GPIO pins and your program is done, you need to run "GPIO.cleanup()" so you don't get error messages.

Laurens

Fantastic, tanks a lot, and thanks for the heads up on the GPIO.cleanup()

[Kimovitzh]

you could do something like this:

Code: Select all

import RPi.GPIO as GPIO
from time import sleep

GPIO.setmode(GPIO.BOARD)
GPIO.setup(16, GPIO.OUT)
GPIO.output(16, 1)
sleep(0.1)
GPIO.output(16,0)
GPIO.cleanup()

After you used the GPIO pins and your program is done, you need to run "GPIO.cleanup()" so you don't get error messages.

Laurens

Hi again, is there a way to do the same code, but instead of starting with a 1 and ending with a 0, start with 0 and end with 1?

I tried the obvious by just editing the script and replace 1 with 0 and visa versa. But I doesn't work.

Any ideas?

[rpdom]

Hi again, is there a way to do the same code, but instead of starting with a 1 and ending with a 0, start with 0 and end with 1?

I tried the obvious by just editing the script and replace 1 with 0 and visa versa. But I doesn't work.

Any ideas?

That's because of the GPIO.cleanup. What that does is to set the GPIOs used by your program back to the default levels and modes.

So, your program sets pin 16 to output, then sets it to a "1" (high) state. Then you run GPIO.cleanup which puts it back to "0" again. Take out the cleanup if you want to leave the pin in the state you set it to.