Multiple displays on the Pi


19 posts
by cajundust » Tue Nov 06, 2012 8:19 pm
Hello,

I am looking for suggestions or pointers to connect multiple displays on the raspberry pi, running the arm linux, and displaying 2 independent screens (not mirror).

Preferable, one of the 2 screens is a touchscreen.

What I want to to is provide a sort of 2-display system, where an operator has the touch enabled screen,and the other person is just observing the second screen output.

I hope the community can help me get started...
Posts: 5
Joined: Tue Nov 06, 2012 8:11 pm
by Burngate » Wed Nov 07, 2012 10:20 am
The Pi on its own can only drive one screen - be it HDMI or composite.
There are USB screens, which may interface with the Pi.

A maybe better alternative would be two Pis networked together.
If you don't supply a mouse and keyboard for the second Pi, then that one can only be watched!
Brain surgery is easier than psychoanalysis
User avatar
Posts: 2636
Joined: Thu Sep 29, 2011 4:34 pm
Location: Berkshire UK
by mahjongg » Wed Nov 07, 2012 10:35 am
The raspberry PI foundation is working on an interface that would make it possible to add an LCD panel, and this panel will indeed be useable as a seconds screen, independent of the HDMI screen. The interface connector is located above the SD-Card slot, a second similar connector is for a planned camera module.
User avatar
Forum Moderator
Forum Moderator
Posts: 4869
Joined: Sun Mar 11, 2012 12:19 am
by cajundust » Wed Nov 07, 2012 12:13 pm
Hello,

Thanks for the replies.
So, the analog video and HDMI cannot be used simultaneously as 2 separate screens.

I believe there is already a connector on the type B board, to connect a LCD. But I cannot find any good starters about how and which hardware to connect. Is it also exclusive ? E.g. when connected, the hdmi or analog will not work anymore ?

Where can I follow the status ?

The other solution, to connect 2 pi's via network, is the last resort solution...
Posts: 5
Joined: Tue Nov 06, 2012 8:11 pm
by mahjongg » Fri Nov 09, 2012 4:13 pm
So, the analog video and HDMI cannot be used simultaneously as 2 separate screens.


No!

believe there is already a connector on the type B board, to connect a LCD. But I cannot find any good starters about how and which hardware to connect. Is it also exclusive ? E.g. when connected, the hdmi or analog will not work anymore ?

the DSI output will function as a second screen, and will be fully independent of the main screen.
At least AFAIK.

Where can I follow the status ?

It will be announced on the News page (front screen), it will be ready when its ready, my best guess will be early 2013, but you won't hear when its ready until it is ready.

The other solution, to connect 2 pi's via network, is the last resort solution...


That is one possibility, the other is to use the same screen twice. Connect the composite video output of the PI to two TV's, and mask a different part of each TV's screen. For example on one screen the top half, and on the other the bottom half.
User avatar
Forum Moderator
Forum Moderator
Posts: 4869
Joined: Sun Mar 11, 2012 12:19 am
by toxibunny » Fri Nov 09, 2012 6:24 pm
You could use a USB video card, or a graphical LCD module attached to the GPIO. Performance will probably be pretty poor though...
note: I may or may not know what I'm talking about...
Posts: 1047
Joined: Thu Aug 18, 2011 9:21 pm
by zardoz66 » Thu Jan 03, 2013 2:24 am
Mmm, I have a USB display link adaptor. I might half to try this...
Zardoz
Raspberry Pi B v2.0 | Sony 16GB SDHC Class 10 | Cyberpower CPH420P 4 port USB HUB | Netis WF-2111 150Mbps Wireless-N USB | Sabrent CRW-EXT 6-Slot Card Reader | MS USB Notebook Optical Mouse | Mini USB Keyboard | Adafruit Pibow case (blue)
User avatar
Posts: 50
Joined: Wed Jan 02, 2013 1:02 am
Location: Austin TX
by zardoz66 » Thu Jan 03, 2013 3:12 am
tried my usb displaylink adaptor, no go out of the box. reading on it reviled some driver stuff might have to be done to get it working... I will poke at it and see what I can get done...
Zardoz
Raspberry Pi B v2.0 | Sony 16GB SDHC Class 10 | Cyberpower CPH420P 4 port USB HUB | Netis WF-2111 150Mbps Wireless-N USB | Sabrent CRW-EXT 6-Slot Card Reader | MS USB Notebook Optical Mouse | Mini USB Keyboard | Adafruit Pibow case (blue)
User avatar
Posts: 50
Joined: Wed Jan 02, 2013 1:02 am
Location: Austin TX
by gordon@drogon.net » Thu Jan 03, 2013 4:24 pm
Are you looking for a framefuffer type of display, or just a general purpose programmable LCD panel? If it's the latter, then this may help: https://projects.drogon.net/4d-systems- ... pberry-pi/

-gordon
--
Gordons projects: https://projects.drogon.net/
User avatar
Posts: 1487
Joined: Tue Feb 07, 2012 2:14 pm
Location: Devon, UK
by zardoz66 » Thu Jan 03, 2013 4:38 pm
Hello Gordon,

Think he is looking to do somting like a multi-display with the RasPi. There is a technoligy called displaylink that alows you to have a USB video card of sort. (this is a pice of hardware) from what I have found so far this might work, but drivers will need to be setup for it, and it's seems to be a bit of work that I have not started yet. hope to have some time this week to mess with it, I am using an EVGA UV-16 to test with.
Zardoz
Raspberry Pi B v2.0 | Sony 16GB SDHC Class 10 | Cyberpower CPH420P 4 port USB HUB | Netis WF-2111 150Mbps Wireless-N USB | Sabrent CRW-EXT 6-Slot Card Reader | MS USB Notebook Optical Mouse | Mini USB Keyboard | Adafruit Pibow case (blue)
User avatar
Posts: 50
Joined: Wed Jan 02, 2013 1:02 am
Location: Austin TX
by zardoz66 » Fri Jan 04, 2013 4:14 am
ok, I found a link that shows how to get a display link device working. it will require a compile of the the raspbian kernel some drivers and configure a /etc/X11/xorg.conf file. anyways looks like it can be done. here is the link to what I found.

http://karuppuswamy.com/wordpress/2012/ ... -raspbian/

I dont have the resource to compile something like this at the moment.
Zardoz
Raspberry Pi B v2.0 | Sony 16GB SDHC Class 10 | Cyberpower CPH420P 4 port USB HUB | Netis WF-2111 150Mbps Wireless-N USB | Sabrent CRW-EXT 6-Slot Card Reader | MS USB Notebook Optical Mouse | Mini USB Keyboard | Adafruit Pibow case (blue)
User avatar
Posts: 50
Joined: Wed Jan 02, 2013 1:02 am
Location: Austin TX
by sdc.engine » Tue Nov 05, 2013 11:59 am
Hi there,

I'm also trying to connect several displays at once to rpi in order to create a sort of video shell.
My idea is to connect 3or4 TFT's (each one with its own MCU as graphic driver) to rpi via serial or parallel interface, but I don't know how to do for split the video on rpi and send the video-parts to each screen.

have you some advice or alternative?

#thanks4yourcooperation
Posts: 6
Joined: Mon Nov 04, 2013 11:59 am
by RaTTuS » Tue Nov 05, 2013 12:06 pm
1QC43qbL5FySu2Pi51vGqKqxy3UiJgukSX - Prosliver FTW
"That's not right, the badgers have moved the goalposts."
User avatar
Posts: 4580
Joined: Tue Nov 29, 2011 11:12 am
Location: North West UK
by sdc.engine » Tue Nov 05, 2013 1:35 pm
RaTTuS wrote:http://www.piwall.co.uk/


It's exactly what I was looking for... Thanks RaTTuS ;)
Posts: 6
Joined: Mon Nov 04, 2013 11:59 am
by masonsa » Sun Dec 22, 2013 11:11 pm
Hi All,

I know this thread is a little old, but I was wondering if any one has had success with dual monitor support with HDMI and USB displaying link ? I have successfully rebuilt the kernel with frame buffer support, and can get the displays to work independently, but not together. Does anyone have a working xorg.conf that will enable both screens to give an extended desktop ?

Cheers,
Stephen.
Posts: 7
Joined: Sun Dec 22, 2013 10:42 pm
by ana.domingos » Wed Jun 25, 2014 4:52 pm
Hi,

I received the 2,8'' TFT v2 and I was able to make it work for the touch screen with the image in viewtopic.php?f=45&t=64993

But now I want to have an extended desktop ( TFT and HDMI). I saw your suggestion to use fbcp and it worked to see the desktop in both sides as a mirror not extended. How can I see the extended desktop in TFT and HDMI?

Thanks.
Posts: 3
Joined: Wed Jun 25, 2014 4:44 pm
by ragnarjensen » Thu Jun 26, 2014 9:22 am
We had a discussion a while ago on how to create an extended desktop.
viewtopic.php?p=473226#p473226
--
Ragnar
Last edited by ragnarjensen on Fri Jun 27, 2014 9:22 am, edited 1 time in total.
User avatar
Posts: 171
Joined: Wed May 15, 2013 6:13 pm
Location: Stockholm, Sweden
by ana.domingos » Thu Jun 26, 2014 5:22 pm
That's what I needed. Thanks.
Posts: 3
Joined: Wed Jun 25, 2014 4:44 pm
by ana.domingos » Mon Jun 30, 2014 10:55 am
I have a new problem: every time I touch in the screen the result is always shown in fb0 (HDMI). (It does not depend on the primary screen, because I've set TFT as primary and still have the same problem).

I've seen config files of Xorg with InputClass that verify MatchIsTouchScreen, but I don't see any relation of InputClass with framebuffers. How can make the touch input being displayed in fb1?

Thanks.
Posts: 3
Joined: Wed Jun 25, 2014 4:44 pm