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

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)

MadScientist

I did that in the very beginning but then relay isn’t working at all. It only works with 3.3V. No idea why.

randomnoise

@MadScientist

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.

That pretty much sums up my experience as well… I used to have the pir module working great (I didn’t use a relay, just screen off/on). It started acting up so I tried all of the following:
Using script
Putting pir sensor in a box to avoid trigger sources
A different pir sensor (same type as I had previously working)
Completely different type of pir sensor
Complete rebuild of pi from scratch & reinstall mm.
An acoustic noise driven sensor.

No matter what I did I get random triggers usually every couple of mins. All I can think is its either an issue with the input ‘floating’ and being pulled down (all though tried pull up & pull down option in wiring pi).

Only thing I can think is that I’ve possibly fried my gpio somehow.

Anyway I went with a pir / relay which is stand alone so doesn’t use the pi to turn monitor on / off.

Be interested if you ever manage to resolve the random triggers.

MadScientist

What independent PIR are using now? Can give me link? I was looking into it too, but couldn’t find one that runs on 12V only. They all have 230V input and 12V output. That’s not working for me.
When you used the PIR with the GPIO pins, did you use a ferrit ring with it? Apparently that can help. I also had phantom triggers when I only used the PIR (without relay) and the MMM-PIR-sensor module. The ferrit ring resolved the phantom triggers for me 100%. Just now with the python script and the relay I get them very randomly. Sometimes after 2 minutes, sometimes after 2 hours.

cruunnerr

Thats how i tested and it works like a charm. I just set up a fresh raspbian stretch Desktop.
There was no need to install wiring-pi! the scripts just ran “out of the box”.

PIR: https://www.amazon.de/Aukru-HC-SR501-Menschliche-Pyroelektrizität-Bewegungssensor/dp/B00R2U8LLG

randomnoise

@MadScientist I went with this one. Only thing is it ain’t pretty so I’m looking to build it in to a nicer enclosure to increase the WAF.

I didn’t try using a ferrite ring, but I’ve got a few kicking around. Maybe worth a go.

link text

randomnoise

Should say, I’m just switching the ac in for monitor power directly…

MadScientist

This is how my setup looks like at the moment:
alt text
Relay: Black = GND, white = Vcc 3.3V, green = IN
PIR: Black = GND, red = Vcc, green = out

Gray, blue, puple = ds18b20 temperature sensor.

I actually haven’t had a false trigger yet and the Pi is running for more than an hour now. I will keep it running the whole day. Have a multimeter connected to the relay, set to continuity test, so I should hear a beeping sound every time the relay gets triggered.

cruunnerr

@MadScientist

sounds like a good plan :)

edit:
i also made changes to the scripts so now u were able to end them via “ctrl+c”.
Don’t know if i did everything correct but it works here. :)
I am just electronics technician and no programer ^^

hoofta

I got really excited to see this post when it was shared a few weeks ago. Unfortunately, I have yet to get it to work. I am using a PIR sensor along with Paviro’s module. My issue is that I am using an LG TV which, when the signal is no longer received from the HDMI port, a “no signal” screensaver bounces around. So my goal is to get the screen to just go to black while the raspberry pi does not enter a power-save mode.

I have attempted to use the “screen_off/on” option original provided instead of the “monitor_on/off” but it doesn’t seem to be working properly.

I have tested that the PIR is connected but in my test it keeps teling me that motion is detected when there is no movement. I am doing this through a python script. I am fairly new at this so if anyone can please let me know what else I can provide you to help me get this thing working with the PIR sensor. Thanks.

MadScientist

@hoofta Couldn’t you use a relay (like me) but instead of disconnecting the power you just trigger the power on/off button?

hoofta

@MadScientist I am not sure if I could or not. Could you elaborate on how you have yours setup?

MadScientist

@hoofta My mirror isn’t done yet but in my case the relay will disconnect the power from the power supply to the LCD. I have no idea what TV you’re using but you could solder 2 wires to the power button of your TV and connect them to a relay, which will be triggered by a PIR motion sensor.

cruunnerr

@hoofta said in {HowTo} turn on/off your monitor (Time based, PIR/Button, App):

I have attempted to use the “screen_off/on” option original provided instead of the “monitor_on/off” but it doesn’t seem to be working properly.

As described u need to use the “pir.py” script from point 2.2.
But then (and i forgot to write that) u need to change the shell script names in the script or keep the “monitor_on” as name.
Sorry for my english, i hope u understand.

So, to help u out:
u already creates the “screen_on.sh” and “screen_off.sh”, right?

then u need to change the following lines in the “pir.py” script like this:

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

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

The idea to connect the power button of the TV to a relay is a good start. So u could save much money.

But then the relay must do an impulse instead of being on or off static.

To do this u could use the normal pir.py script from point 2.2 (without any changes).
But the content of both *.sh files should look like this:

nano monitor_on.sh :

gpio -g write 27 1
sleep 1
gpio -g write 27 0

nano monitor_off.sh :

gpio -g write 27 1
sleep 1
gpio -g write 27 0

chmod +x monitor_on.sh
chmod +x monitor_off.sh

Connect the relay with two wires parallel to the power button of your tv.
On the relay use “C” and “NO”

hoofta

@cruunnerr I did see originally where the monitor_on/off.sh needed to have the word “monitor” replaced with “screen” in the pir.py script. I am not sure I am confident enough to solder in a relay to the power switch on my TV. :-/

What script do you use to confirm your PIR is hooked up correctly and receiving the proper signal/input?

cruunnerr

@hoofta said in {HowTo} turn on/off your monitor (Time based, PIR/Button, App):

What script do you use to confirm your PIR is hooked up correctly and receiving the proper signal/input?

Just use the pir.py script from the tutorial ;)

every movement will show some dots in your terminal

hoofta

@cruunnerr Right, sorry about that. I forgot you included it. When I did that during initial setup, the dots scrolls across without stopping. Motion or not, dots keep generating.