Rpi 4 and two monitors

[NathTheDude]

Has anyone tried building a MM with an rpi4 and attaching two monitors?

I wanted two hook up to 21.5 inch monitors as it would be cheaper than getting a slim 30+ inch monitor.

[sdetweil]

@NathTheDude it should be simple, it appears the dual monitors is one big desktop by default.

MM should extend over both as one single display.

[NathTheDude]

@sdetweil thanks.

I found it had to get cheaper monitors that are both slim and gave small bezel. Not sure how will look with about 3-4cm of bezel in the middle.

[chassain 0]

i tried to use a rpi4 with 2 hdmi on the same tv and the result is ok. You just need to adjust resolution on screen menu hdmi 1 and hdmi 2.
It’s a solution for my work to use only one raspberry with 2 screen televisions.

[NathTheDude]

Hey @sdetweil and @chassain-0 , so my kit for my v2 project has arrived. I have two 21.5 inch (same model) monitors connected up to an RPI4.

I have had a look around the forum but not been able to see what the best method is for this. When we start pm2 or when the RPI reboots it will boot up with the MM on the first screen and the normal desktop seen on the 2nd screen.

I think I would prefer to have two MM’s installed (one for each monitor), I assume this is ok todo or is the best approach to have the one MM on both screens?

Thanks

Nathan

[NathTheDude]

I wondered if I needed to update the ‘mm.sh’ file within the ‘installers’ folder, I tried changing this from ‘0’ to ‘1’ - reboot the RPI but on reboot MM does not get started on either monitor.

---

pi@MagicMirrors:~/MagicMirror/installers $ tvservice --list
2 attached device(s), display ID’s are :
Display Number 2, type HDMI 0
Display Number 7, type HDMI 1

[bhepler]

@NathTheDude - I tried that one-pi-two-instances thing a couple years ago. I wasn’t using an RPI but rather a tiny Ubuntu box. My problem was that I couldn’t find a way to guarantee which instance would appear on which monitor at start. They usually both ended up in the same monitor on top of each other.

You may have more luck than I did. If you do figure it out, please let me know how you did it!

[sdetweil]

@NathTheDude said in Rpi 4 and two monitors:

think I would prefer to have two MM’s installed (one for each monitor), I assume this is ok todo or is the best approach to have the one MM on both screens?

the answer is yes, … depends on what you want to do…

to use two MM on the same full width display you will have to modify custom.css on the one to the right
and make its starting position 1/2 way across the screen

when MM is on the left, is the desktop a full image, or just the right side of the full image?

[NathTheDude]

Hey @sdetweil , I started with stopping MM (pm2 stop all). This then allowed me to use VNC to change the screen settings, as in just rotate the screen’s display.

The screens are showing as two seperate desktops and from VNC the mouse smoothly goes from one display to the other.

When MM is started this completly fills the first screen and a raspbian windows desktop is seen on the 2nd screen.

[sdetweil]

@NathTheDude try the raspian, preferences, appracne settings, desktop stretch across