Turning TV on/off via PIR sensor - current problem: TV displays "No Signal" screen

mcmalone

Problem: I want to turn the screen off/on depending on when the PIR sensor detects motion. It seems that the sensor is working, but when the TV is “off” instead of a black screen, it displays “No signal.” The TV is CEC-enabled, so I am under the impression that my goal should be possible.

I am using a RBP 4. Given that the screen does activate when movement is detected, I am assuming that the PIR sensor is properly connected.

Currently, I have the following Python script, pir.py, run on start:

#!/usr/bin/env python

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

io.setmode(io.BCM)
SHUTOFF_DELAY = 10 # in seconds, how long the monitor will be on until next button press or PIR detection
PIR_PIN = 4       # 7 on the board (this needn't to be a PIR. Can be a button also)
#LED_PIN = 16      # optional, don't use as Relay-PIN. It just shows detection time of the PIR without delay time

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()

monitor_on.sh reads: sudo vcgencmd display_power 1 7

monitor_off.sh reads: sudo vcgencmd display_power 0 7

I have tried:

Using tvservice -o and tvservice -p instead of vcgencmd display_power. While the TV would turn off, it would not turn back on. (I only tried -p option, never -e. I don’t know if that makes a difference.)
Using the MMM-PIR-Module which is a module for MagicMirror. These were the module settings I used:

{
		module: 'MMM-PIR-Sensor', 
		position: "top_center", // Remove this line to avoid having an visible indicator
		config: {
			sensorPin: 4,
			powerSavingDelay: 60, // Turn HDMI OFF after 60 seconds of no motion, until motion is detected again
			preventHDMITimeout: 4, // Turn HDMI ON and OFF again every 4 minutes when power saving, to avoid LCD/TV timeout
			supportCEC: true, 
			presenceIndicator: "fa-eye", // Customizing the indicator
			presenceOffIndicator: "fa-eye", // Customizing the indicator
			presenceIndicatorColor: "#f51d16", // Customizing the indicator
			presenceOffIndicatorColor: "#2b271c" // Customizing the indicator
		}
	}

Sometimes I felt the module was not working, not turning the TV back on when there was motion. Other times, if working, it still produced the No Signal screen, instead of a blank screen.

Thank you in advance for any help!

mcmalone

@mcmalone I don’t know exactly why but the following solution worked for me.

Posting my solution for others in the future and also so that maybe someone in the future can explain to me why this works (and maybe a more efficient solution).

I changed the monitor_on.sh and monitor_off.sh files to read, respectively:

DISPLAY=:0 xscreensaver-command -deactivate

and

DISPLAY=:0 xscreensaver-command -activate

Before I made these changes, I also configured xscreensaver by running xscreensaver-demo in the terminal, then on my monitor connected to the Pi, a preferences box pops up. I selected “black screen” from the options so that when the screensaver activates through the above files, it will be a black screen (no backlight).

lavolp3

@mcmalone said in Turning TV on/off via PIR sensor - current problem: TV displays "No Signal" screen:

@mcmalone I don’t know exactly why but the following solution worked for me.

Posting my solution for others in the future and also so that maybe someone in the future can explain to me why this works (and maybe a more efficient solution).

I changed the monitor_on.sh and monitor_off.sh files to read, respectively:
DISPLAY=:0 xscreensaver-command -deactivate
and
DISPLAY=:0 xscreensaver-command -activate
Before I made these changes, I also configured xscreensaver by running xscreensaver-demo in the terminal, then on my monitor connected to the Pi, a preferences box pops up. I selected “black screen” from the options so that when the screensaver activates through the above files, it will be a black screen (no backlight).

With this procedure you are turning on the screensaver (which is set to black) instead of turning the screen off.
It may serve as a solution wiht regard to the picture, but keep in mind that 1) a black screen is brighter than a screen turned off (except you have an oled screen) 2) you are wasting power.
My screen consumes ~ 20W running, my pi consumes ~ 2W.
I’d rather have the screen turned off in absence of any person.

Still, I had the same problem for some time.
Last time I tried the MMM-NewPIR module it worked for me. That one has a configuration option for the different modes (display_power vs tvservice).
You may have a look into that module.

mcmalone

@lavolp3 said in Turning TV on/off via PIR sensor - current problem: TV displays "No Signal" screen:

With this procedure you are turning on the screensaver (which is set to black) instead of turning the screen off.
It may serve as a solution wiht regard to the picture, but keep in mind that 1) a black screen is brighter than a screen turned off (except you have an oled screen) 2) you are wasting power.
My screen consumes ~ 20W running, my pi consumes ~ 2W.
I’d rather have the screen turned off in absence of any person.

Hmm, the TV does not appear to emit any light with my current settings. I turned off all the lights and I do not see anything being emitted from the TV screen, no backlight. Of course, I’m not really sure if it could still be using more power and I’m just not aware. Is there a way I could check? Or perhaps the TV still consumes power because it is still “on”?

Still, I had the same problem for some time.
Last time I tried the MMM-NewPIR module it worked for me. That one has a configuration option for the different modes (display_power vs tvservice).
You may have a look into that module.

Thank you, I will look into this! I was not aware of this module. I had only heard of the other one I had mentioned above.

MadScientist

@mcmalone If you use a screensaver then I am 99.9% sure the TV is still on, just showing a black screen.
Maybe have a look at MMM-NewPIR. It supports HDMI-CEC and should turn your TV on/off. Otherwise you try the relay method explained by @cruunnerr in this HowTo.