Multiple displays on the Pi


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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...
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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!
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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.
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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...
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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.
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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...
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by zardoz66 » Thu Jan 03, 2013 2:24 am
Mmm, I have a USB display link adaptor. I might half to try this...
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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...
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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/

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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.
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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.
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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
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by RaTTuS » Tue Nov 05, 2013 12:06 pm
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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 ;)
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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.
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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.
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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
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Last edited by ragnarjensen on Fri Jun 27, 2014 9:22 am, edited 1 time in total.
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by ana.domingos » Thu Jun 26, 2014 5:22 pm
That's what I needed. Thanks.
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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.
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by StangPi » Fri Feb 26, 2016 12:35 pm
I am trying to run 2 cameras using a multiplexer and having the feeds sent to separate TFT screens.

I've been told that it would be best to accomplish this by connecting 2 RPi.

Is there any possible way to connect to TFT screens to a single RPi?
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by 6by9 » Fri Feb 26, 2016 1:00 pm
StangPi wrote:I am trying to run 2 cameras using a multiplexer and having the feeds sent to separate TFT screens.

I've been told that it would be best to accomplish this by connecting 2 RPi.

Is there any possible way to connect to TFT screens to a single RPi?

The renderer won't know which camera is selected, so there's no synchronisation.
Use a Compute Module with both cameras directly connected and you should be able to tell them to each render to either HDMI, 7" touchscreen, or composite by setting an appropriate display number.
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by StangPi » Fri Feb 26, 2016 1:32 pm
6by9 wrote:
StangPi wrote:I am trying to run 2 cameras using a multiplexer and having the feeds sent to separate TFT screens.

I've been told that it would be best to accomplish this by connecting 2 RPi.

Is there any possible way to connect to TFT screens to a single RPi ?

The renderer won't know which camera is selected, so there's no synchronization.
Use a Compute Module with both cameras directly connected and you should be able to tell them to each render to either HDMI, 7" touchscreen, or composite by setting an appropriate display number.


A few questions:
1-Compute Module? Like the camera Multiplexer ill be purchasing?
2-Would be nice to somehow use 2 TFTs. The location where I'll install them is quite small and only a TFT or similar sized screen would fit. How would i go about combining two Pi's to achieve this which would also delete the need for the multiplexer.
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by RaTTuS » Fri Feb 26, 2016 2:04 pm
http://uk.rs-online.com/web/p/products/8268825/
or
http://uk.rs-online.com/web/p/processor ... s/8134164/

hacking multiple camera on a normal RPi will not give you what you want
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by StangPi » Fri Feb 26, 2016 2:15 pm
RaTTuS wrote:http://uk.rs-online.com/web/p/products/8268825/
or
http://uk.rs-online.com/web/p/processor ... s/8134164/

hacking multiple camera on a normal RPi will not give you what you want


There is a RPi Camera Multiplexer: http://www.ivmech.com/magaza/en/develop ... lexer-p-90
Waiting on an email reply from the company about this product.

IF there is anyway to accomplish using 2 PiTFTs and somehow direct the separate camera feeds to each TFT I would be excruciatingly overjoyed.
If it comes to the point that there is no way to do this then i will have to use 2 RPi's w/ their own cameras.

I would really like to be able to use only 1 Pi, but if it comes down to it then i will use 2 .
Until i feel there is no other way, i will keep looking lol.
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by RaTTuS » Fri Feb 26, 2016 2:22 pm
2x camera via that you will not get it to direct to 2x tft [are these GPIO screens? - you will have frame rate issues]

the best way for 2x camera and 2x display is to use 2x RPi and camera and hdmi screens that will give you 30fps

or use hdmi to tft adapters

using the CM will give you 2x RPi camera and 2x RPI display [yes ? should work] and you can build your own board for extra smallness for what you need
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