switch off the monitor

[wwwlu]

Hi, I try to create a mural display monitor to show rss flows
I have an orange pi pc plus with armbian installed on EMMC and a RVB monitor with an RVB/HDMI adapter.
I don't want the monitor to be ON permanently (for monitor longevity and energy savings)
So I plan to have an IR sensor to detect human presence and set the monitor on/off
My prefered option would be to use the GPIO for the sensor.

My DPMS configuration is :
Section "Monitor"
        Identifier      "Monitor0"
        Option          "DPMS" "true"
EndSection
Section "ServerFlags"
    Option         "BlankTime" "0"
    Option         "StandbyTime" "0"
    Option         "SuspendTime" "0"
    Option         "OffTime" "1"
EndSection
After one minute of inactivity the screen turns black BUT it is not really in sleep mode.
How can I manage to really switch off the monitor ?
If not possible I could -as plan B- use an arduino with a relay to power off the monitor (or cut the ground wire of the RGB cable) but this is definitelly not my prefered option
Can you help ?

[wwwlu]

ok, I got the solution...
I installed XFCE power manager and it works fine now