@cruunnerr @MadScientist Thanks to both of you . For development/tutorial and support. My MM works. I was probably impatient the whole time I was testing. The relay only switches for the first time after the 120 s have expired. But that’s ok that it only occurs when you restart. I consider the problem solved. THANK YOU

@MadScientist ok it seems to be working now. However, the relay switches the first time after the 120 s have expired and a movement is detected. not previously. The change quote: “io.output(RELAY_PIN, False)” and for monitor off “io.output(RELAY_PIN, True)” only causes the relay to work in reverse. I now use this script:

#!/usr/bin/env python

import sys
import time
import RPi.GPIO as io
import subprocess

io.setmode(io.BCM)
SHUTOFF_DELAY = 120 # in seconds, how long the monitor will be on until next button press or PIR detection
PIR_PIN = 22       # 15 on the board (this needn't to be a PIR. Can be a button also)
LED_PIN = 17    # 11 on the board (optional): It just shows detection time of PIR without delay time
RELAY_PIN = 27  # 13 on the board

def main():
    io.setup(PIR_PIN, io.IN)
    io.setup(LED_PIN, io.OUT)
    io.setup(RELAY_PIN, io.OUT)
    turned_off = False
    last_motion_time = time.time()

    while True:
        if io.input(PIR_PIN):
            last_motion_time = time.time()
            io.output(LED_PIN, io.LOW)
            print ("."),
            sys.stdout.flush()
            if turned_off:
                turned_off = False
                turn_on()
        else:
            if not turned_off and time.time() > (last_motion_time + 
                                                 SHUTOFF_DELAY):
                turned_off = True
                turn_off()
            if not turned_off and time.time() > (last_motion_time + 1):
                io.output(LED_PIN, io.HIGH)
        time.sleep(.1)

def turn_on():
        io.output(RELAY_PIN, True)

def turn_off():
        io.output(RELAY_PIN, False)

if __name__ == '__main__':
    try:
        main()
    except KeyboardInterrupt:
        io.cleanup()

where could the error lie? or is that how it should be? Thank you MadScientist

@MadScientist Hey, unfortunately the problem hasn’t changed. I have now like you said the script from 5.2. The problem remains. PIR detects motion. Relay does not switch. :loudly_crying_face: I don’t know

Hello everyone, I’m getting desperate. I’ve now read the entire tutorial but I can’t find my mistake.

I am using my MM with a PIR sensor and would like to switch the backlight of the display with a relay. so i use this script pir.py:

#!/usr/bin/env python

import sys
import time
import RPi.GPIO as io
import subprocess

io.setmode(io.BCM)
SHUTOFF_DELAY = 120 # in seconds, how long the monitor will be on until next button press or PIR detection
PIR_PIN = 22       # 15 on the board (this needn't to be a PIR. Can be a button also)
LED_PIN = 16      # optional

def main():
    io.setup(PIR_PIN, io.IN)
    io.setup(LED_PIN, io.OUT)
    turned_off = False
    last_motion_time = time.time()

    while True:
        if io.input(PIR_PIN):
            last_motion_time = time.time()
            io.output(LED_PIN, io.LOW)
            print ".",
            sys.stdout.flush()
            if turned_off:
                turned_off = False
                turn_on()
        else:
            if not turned_off and time.time() > (last_motion_time + 
                                                 SHUTOFF_DELAY):
                turned_off = True
                turn_off()
            if not turned_off and time.time() > (last_motion_time + 1):
                io.output(LED_PIN, io.HIGH)
        time.sleep(.1)

def turn_on():
	subprocess.call("sh /home/pi/monitor_on.sh", shell=True)

def turn_off():
	subprocess.call("sh /home/pi/monitor_off.sh", shell=True)

if __name__ == '__main__':
    try:
        main()
    except KeyboardInterrupt:
        io.cleanup()

Unfortunately, when I run this script in the terminal, I only get the feedback from the PIR sensor (…) but the relay is not switched. But if I run the monitor_on.sh or monitor_off.sh script it works:

monitor_on.sh

gpio -g mode 27 out
sleep 0.2
gpio -g write 27 1

monitor_off.sh

gpio -g mode 27 out
sleep 0.2
gpio -g write 27 0

But the PIR.py doesn’t work. Where could the mistake lie?

Many greetings Andreas