Switching the Magic Mirror display on/off

Hilt

What you’re describing in Home Assistant sounds like a switch, not a button. They have different behaviours. This is important for what follows.

Initially I had our mirror turning on/off on a schedule using crontab. But when I rebuilt it recently, I too wanted some Home Assistant integration to make this a little more intelligent ( turn on/off with the alarm system for e.g. )

I went a different route and installed an SSH integration in Home Assistant ( there are enough modules on the long suffering Pi 3B+ ! )

Using this integration, any SSH command can be turned into button like so :

Screenshot (1).png

If you’re using a Pi, you can use the following in the configuration options of the integration :

Screenshot (2).png

The actual code for your ease of use :

- command: sudo shutdown -h now
  name: Turn off
  key: turn_off
- command: sudo reboot
  name: Restart
  key: restart
- command: vcgencmd display_power 0
  name: Turn Screen Off
  key: turn_offf
- command: vcgencmd display_power 1
  name: Turn Screen On
  key: turn_on

That vcgencmd display_power command should work on pretty much an HDMI monitor

This results in a bunch of buttons that you can use in your Home Assistant automations

Screenshot (3).png

sdetweil

@Hilt vcgencmd no longer works on Bullseye (last release) or Bookworm (this release) of PI os

@Hilt said in Switching the Magic Mirror display on/off:

vcgencmd

Hilt

@sdetweil

Thanks for the heads up Sam.

I’m currently running Bullseye with kernel 6.1.21-v7+ and it still works in this revision. Admittedly I didn’t try with Bookworm as when I originally tried it ( Bookworm ) at launch, the VNC server had gone away on account of Wayland and alternatives were…interesting back then ( didn’t do too much research at the time to be fair ). So for this rebuild I just stuck with Bullseye.

2 quick questions for my own edification :

For Bookworm. Could the commands I listed for vcgencmd simply be replaced with wlr-randr --output HDMI-A-1 --on and wlr-randr --output HDMI-A-1 --off ( assuming HDMI port 1 ) for the same result ?
Another option according the the almighty but not always correct ChatGPT is to switch to X11 and then vcgencmd would work as expected ?

I have a spare Pi I could test on. I won’t however have time to tinker in the next few weeks. Curse having to adult !!

Really appreciate your input

sdetweil

@Hilt said in Switching the Magic Mirror display on/off:

Another option according the the almighty but not always correct ChatGPT is to switch to X11 and then vcgencmd would work as expected ?

no, this is incorrect, as vcgencmd is no more , altho I see it on my bookworm system , it is not supposed to support display anymore…

as for point 1,
when running wayland you can use the wlr-randr command
when running x11 you can use the xrandr command

I don’t know the specifics of what each command needs.

all linux commands come with help built in

wlr-randr --help

many provide more detailed info in the man page
man wlr-randr
I see the man page for vcgencmd is there too

Klinge

First of all, thank you for your tips.

So, I use the module from ambarusa

origin  https://github.com/ambarusa/MMM-HomeAssistant/ (fetch)
origin  https://github.com/ambarusa/MMM-HomeAssistant/ (push)

And use the following config

                   module: “MMM-HomeAssistant”,
                   config: {
                        mqttServer: “mqtt://192.168.100.xx”,
                        mqttPort: 1883,
                        username: “mqttxxxx”,
                        password: “xxxxx”,
                        deviceName: “MagicMirror xxxx”,
                        autodiscoveryTopic: “homeassistant”,
                        monitorControl: true,
                        brightnessControl: true,
                        moduleControl: true,
                        monitorStatusCommand: “xrandr --query | awk \”/Screen/ {print ($8 > 320) ? ‘true’ : ‘false’}\“”,
                        monitorOnCommand: “wlr-randr --output HDMI-A-1 --on --transform 90”,
                        monitorOffCommand: “wlr-randr --output HDMI-A-1 --off”,
//                      monitorOnCommand: “xrandr -d :0 --output HDMI-1 --auto --rotate right”,
//                      monitorOffCommand: “xrandr -d :0 --output HDMI-1 --off”,
                        pm2ProcessName: “mm”,
                    }

As you can see, I use wlr-randr for on/off and rotate the monitor 90 degrees when switching it on.

Klinge

I think you’re right in calling it a switch. You can see it clearly in the screenshot at the arrow.

Hilt

@sdetweil

Many thanks for the input. I’ll have a tinker when I find a gap and explore the commands and their respective soft switches. Just so that I’m future proof !