I am running Debian on my Pi and I'm using it for a magic mirror. I originally wanted to just prevent the screen from being blank after 10 minutes and keep it on 24/7. So I opened /etc/lightdm/lightdm.conf and added xserver-command=X -s 0 dpms which did the trick.

The issue now is that the backlight from the monitor is too bright during the nighttime, and it would be more optimal if I could have it running from 6:00am to 11pm. Is there any method that can disable the screen from turning off only during a certain time frame? Thanks!

  • What type of screen and how is it connected to the Pi? Sep 22, 2017 at 2:49
  • It's a standard computer monitor that's connected with VGA cables.
    – Jordan
    Sep 22, 2017 at 22:15

1 Answer 1


You can toggle HDMI-output on/off with a cron-job triggered at 6:00am and 11:00pm.

Info about the command to run at these times are located here: https://glframebuffer.wordpress.com/2013/08/28/raspberrypi-how-to-turn-off-hdmi-from-raspberry-pi/

When the HDMI-output is turned off, your monitor will eventually go into power-saving mode and turn off the screen backlight. When HDMI-output is turned on, the monitor will resume back to normal operating mode.

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