PIR Sensor

[tinsebayacc]

Hi, i have recently started building a smart mirror. Its taken me a while (software side) but i am getting there. My only issue is the PIR sensor. I have followed a tutorial and have it working great. It switches off my tv and turns it back on again. The problem is the no signal back ground i have when it switches off. I have a lg tv and its got an annoying cube that bounces around the screen. My question is how do i turn my screen black and not off. I have read some articles but i have not found any that work for me. I am using a PIR.py script and two on/off shell scripts. The shell scripts are as follows

monitor_on.sh
vcgencmd display_power 1

monitor_off.sh
vcgencmd display_power 0

This works perfectly for turning my tv/hdmi off and back on again.
I have read that the following shell scripts should turn the screen black but ive had no luck so far

export DISPLAY=:0
xset dpms force on

export DISPLAY=:0
xset dpms force off

Any help would be appreciated as im a beginner and have run out of ideas. Thanks

[broberg]

Do you have xscreensaver installed? that should do exactly what you are asking
https://www.jwz.org/xscreensaver/man3.html

Or maybe a wifi- wall plug could work better? (i.e cut the power to the tv completly)

[tinsebayacc]

@broberg

Thanks for your response. No I haven’t got that installed. My question is how would I add that into my pir script so that the screen saver came on after a set time and to go off when the pir is activated? Many thanks

[broberg]

@tinsebayacc

Just replace your screen on and off commands with the xscreensaver commands. Should work.

like

for black screen :
xscreensaver-command -activate

and to deactivate black screen :
xscreensaver-command -deactivate

[tinsebayacc]

Thanks again, i have just tried the following but nothing happens. If i run “xscreensaver-command -activate” from the terminal i get

“xscreensaver-command: warning: $DISPLAY is not set: defaulting to “:0.0”.
xscreensaver-command: activating”

It then works and goes into a black screen, same thing for when i deactivate it. But nothing happens when i add it to my sh monitor on/off commands for my pir.py script.

[sdetweil]

@tinsebayacc U need to add

DISPLAY=:0

in front of your command

See the installers/mm.sh for an example

[tinsebayacc]

Thank you, that got rid of that error. Still no joy with the PIR sensor though unfortunately.
The strange thing is if i change my monitor_on and monitor_off sh files to

vcgencmd display_power 0
vcgencmd display_power 1

the pir works fine and shuts off / turns on my monitor.

these are my scrips

#!/usr/bin/env python

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

io.setmode(io.BCM)
SHUTOFF_DELAY = 30 # 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, 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 script

DISPLAY=:0 xscreensaver-command -deactivate

monitor off script

DISPLAY=:0 xscreensaver-command -activate