{HowTo} turn on/off your monitor (Time based, PIR/Button, App)

MadScientist

Two minutes if you know what you’re doing…
The problem is I don’t have a button. I did create the relay.py script and run it. It triggers the relay exactly once and then stays like this. I can’t even stop the script anymore once it’s running…

Man, I really thought setting up the relay would be as easy as adding one line to the config. Wish I had tried to set it up earlier.

Still need help with this. :-(

cruunnerr

Ah I see…
I will write u this evening. We will get it working ;)

MadScientist

Thank you so much!

cruunnerr

@MadScientist
Alright…

Because your relay turns on i think you did everything right. Probably there is a problem with your Module installation… but thats just a guess. Maybe u didn’t give the module the rights to turn on gpio’s?
sudo usermod -a -G gpio pi (the „pi“ at the end stands for your username)

If u did that and it doesn’t work at all you can try to do it with an external script. Follow these steps:

cd
nano monitor_on.sh

put in this:

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

save with “ctrl+x” and “y”

nano monitor_off.sh

put in this:

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

save with “ctrl+x” and “y”

chmod +x monitor_on.sh (to make it executable)
chmod +x monitor_off.sh

nano pir.py

put in this:

#!/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()

save with “ctrl+x” and “y”

chmod +x pir.py

You can check if your button works by simply typing python pir.py. Every time u move through the PIR or press the button it will show you several …
End the test with “ctrl+c”

The Shutoff delay in the script defines how long the relay will be turned on after detection through the pir.

If that works u can add the script to the rc.local to start it automatically when booting up.

MadScientist

Ok, I did all that and I do get the “…” when I run the pir.py, but the relay doesn’t get triggered. Tried the monitor_oX.sh with and without sudo. Maybe I should just start all over new. Everything seems to be a bit messed up. I reverted back to motion detector only and also that isn’t working anymore in MM.

Edit: Started a new thread here.

cruunnerr

@MadScientist
sorry, did a mistake. I edited my post above. just edit the *.sh files.

MadScientist

Thanks a lot to cruunnerr, who has the patience of an angel!

I think there were two problems in my case and I write them here in case someone else has trouble getting the PIR+relay to work.

First: By installing the MMM-PIR-sensor module I used the wrong wiring-pi. npm install wiring-pi installs an old version (2.25) which - so I’ve read - doesn’t work with the Raspberyy Pi 3. It’s best to install wiringpi according to this site.

Second: I used a relay which was supposed to run on 3V to 7V, but apparently that’s not the case. I guess the seller shipped the wrong relay. So I had an old relay lying around which should only run on 5V but it works nicely on my RPi.

Now everything is working, except I get some phantom triggers of the relay every couple of minutes. But I will look into it once everything is set up completely. Maybe I have something around here that can trigger the PIR sensor even if it’s covered by a cloth.

cruunnerr

@MadScientist

that is nice to know… So wiring-pi installs an old version?! Than i need to update my tutorial ^^Thanks mate

And how do you connect the relay? What relay do u use? is it active low or active high? U can try to connect a transistor or an pull up/down resistor to it, so that should disable the trigger from it. If u want to try i can send an image how to connect. It can also be, that your Power supply of the RPi is to small…

MadScientist

The is connected to pin 15 (GPIO 27), 17 (3.3V), and 20 (GND). I tried to post a link to the it, but then this post is flagged as spam. It’s just a cheap relay from Aliexpress.

No idea if that relay is active high or low, but does it matter? It just switches between to connections, so if the relay port 1-2 or 2-3 are active shouldn’t matter, right?

I am using a 3.1A power supply for the Pi. Later I will connected it via a 8A buck-boost-module to a 12V/5A power supply that will power the screen. The Pi will get the power from before the relay so it won’t switch itself off ;-)

Please send a picture, I will gladly try, once I have the extra party I might need (transistor or resistor).

cruunnerr

I am sorry bro, but u did it wrong :(

U need to connect the relay with the 5v pin! Look at my tutorial at around Point 5. There is a picture how to connect. Just leave the button away

Relay                        Raspberry
+                            Pin 2 or 4 (5V)
-                            Pin 6 or any other GND (GND)
in                           PIN 13 (GPIO 27)