Apol
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Re: Portable display for Rasberry Pi

Sun Apr 15, 2012 5:11 pm

Hey guys,

I am looking for a display that is relatively cheap and is also portable to hook up to the Raspberry Pi. I have found some suggestions of using a sat nav which has an input port, however I am unsure if this will work or not?

This is one I have found, what do you guys think?

http://cgi.ebay.co.uk/ws/eBayI.....0924523778

Any help is appreciated,

Cheers

tomtor
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Re: Portable display for Rasberry Pi

Sun Apr 15, 2012 5:54 pm

I see no easy way to attach such a Nav screen to the Pi.

You'll need something like these, which are used for displaying the HD video stream from cameras. These devices have an HDMI video port:

http://www.coollcd.com/lillipu.....46631d9ec2

Apol
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Re: Portable display for Rasberry Pi

Sun Apr 15, 2012 5:59 pm

Thanks for the response.

I did actually notice that exact model. The problem is I was really hoping to pay quite a bit less than the price of that.

tomtor
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Re: Portable display for Rasberry Pi

Sun Apr 15, 2012 6:09 pm

You could look for an old N800, which is like a Pi with a screen

(Arm11, 128MB Ram, 330 Mhz)

http://en.wikipedia.org/wiki/Nokia_N800

Conway
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Re: Portable display for Rasberry Pi

Sun Apr 15, 2012 7:50 pm

I would also like to know of a budget portable display for the Raspberry Pi so could someone maybe offer some constructive advice that isn't completely useless and that actually helps?
Thanks.

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psergiu
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Re: Portable display for Rasberry Pi

Sun Apr 15, 2012 8:05 pm

Search on eBay for "car reverse screen" - the cheapest ones i see now are 13.39 UKP, free shipping - this gets you a 3.5" color 640x480 backlit LCD, 2 composite inputs, 12v power input (power brick not included)

Conway
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Re: Portable display for Rasberry Pi

Sun Apr 15, 2012 8:36 pm

Apol said:


Hey guys,

I am looking for a display that is relatively cheap

Relatively cheap, not something that makes us look poor.

I particularly like the one in the original post so can anyone clarify whether it will work or not?


dawilson123
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Re: Portable display for Rasberry Pi

Sun Apr 15, 2012 9:16 pm

Conway said:


Apol said:


Hey guys,

I am looking for a display that is relatively cheap

Relatively cheap, not something that makes us look poor.

I particularly like the one in the original post so can anyone clarify whether it will work or not?



Something like this:

http://www.ebay.co.uk/itm/3-5-.....549wt_1401

If you can find out what current the device needs, you can pick up a 240V AC to 12V DC transformer. Something like this:

http://www.ultraleds.co.uk/amp.....-2132.html

OR

http://www.ultraleds.co.uk/upw.....cipmkmdh30

You ban pick up the monitor and power supply for less than £30. The problem is that it has a composite video input on the screen and a HDMI to composite video adapter is quite expensive:

http://www.google.co.uk/search.....38;bih=628

saif
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Re: Portable display for Rasberry Pi

Sun Apr 15, 2012 9:38 pm



You ban pick up the monitor and power supply for less than £30. The problem is that it has a composite video input on the screen and a HDMI to composite video adapter is quite expensive


Doesn't the RCA port count as composite Video out? Then all you would need are an audio jack to RCA and bob's your uncle













dawilson123
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Re: Portable display for Rasberry Pi

Sun Apr 15, 2012 10:45 pm

saif said:




You ban pick up the monitor and power supply for less than £30. The problem is that it has a composite video input on the screen and a HDMI to composite video adapter is quite expensive


Doesn't the RCA port count as composite Video out? Then all you would need are an audio jack to RCA and bob's your uncle

I stand corrected. I forgot about the RCA video jack. 











Apol
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Re: Portable display for Rasberry Pi

Sun Apr 15, 2012 11:06 pm

Thanks for all of the responses.

If this is the case, will the original screen work?

http://cgi.ebay.co.uk/ws/eBayI.....0924523778

Cheers.

tomtor
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Re: Portable display for Rasberry Pi

Mon Apr 16, 2012 4:23 am

Apol said:


Thanks for all of the responses.

If this is the case, will the original screen work?

http://cgi.ebay.co.uk/ws/eBayI.....0924523778

Cheers.



No, Dawilson123 suggestion should work, but your link refers to a Nav system which cannot be used as a display device for a video source like the Pi.

I really like Dawilson's screen for an environment where 12V or 220V is available. If you need a screen in an battery powered environment, you could also consider a $80 android tablet:

http://www.ebay.com/ctg/Coby-K.....286.c0.m14

and connect it with Wifi to a Pi (would need some hacking on the Pi so that it acts like an access point) or USB (would require software hacking on both the Android device and Pi). You could use an SSH-client on the tablet to display text from the Pi or enter input or VNC for graphical output.

In above setup it is probably more practical to just forget about the Pi and use such a device which has a screen and ARM processor directly for your application.

What we really need is a dumb and cheap (touch) LCD screen with an USB connection and driver software for Linux. There is another thread about that subject, but such a device does not (yet) exist:

http://www.raspberrypi.org/for.....y-monitor/

Tozzi
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Re: Portable display for Rasberry Pi

Mon Apr 16, 2012 5:41 am

Why must it be a screen from the RCA or HDMI port? There are two special ports on the rpi, one for camera, and one for a LCD (sorry, doesn't remember the names on the ports), shouldn't it be able to use that port instead? Since OP wanted a portable display, I guess it should be "attached" to the RPI(?).

On the picture, it is the one on the left of the RPI-logo, and left to the ethernet port.



zfh10
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Re: Portable display for Rasberry Pi

Mon Apr 16, 2012 6:42 am

everybody wants a small screen.  EVERYBODY.

If you can get a replacement hi-res iphone 4 screen for $17, then surely the technology is affordable and possible.  We just need to make it talk to each other.  The MIPI interface won't work with the Pi's DVI until somebody can figure out the protocol.  I hope the nerds can hurry up! 

Phil Spiegel
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Re: Portable display for Rasberry Pi

Mon Apr 16, 2012 7:07 am

As has been mentioned in previous posts: when using the composite video connector {/hdmi} , the problem is not 'whether a small screen is available' (cheaply or not) but whether any text on it, in console mode, would be sufficiently legible! (as it defaults to an 8x8 matrix, and this is scaled for a 480 or 576 active line display but which is then shown on a 240line LCD panel). European users would benefit from setting config to NTSC!

The only alternative being to use a 'character-based' display - such as an OLED panel eg 2 x 16 (12GBP) or 4 x 20 (24GBP - prices as Picaxe kits inc tax in UK) OR a small tv screen running a terminal emulator in which the font size can be set suitably large - all these using some form of serial [via PICaxe or Terminal Emulator) or 4+ bit wide 'native' connection.

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jojopi
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Re: Portable display for Rasberry Pi

Mon Apr 16, 2012 7:44 am

Phil Spiegel said:


as it defaults to an 8x8 matrix


What defaults to an 8x8 matrix?

Phil Spiegel
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Re: Portable display for Rasberry Pi

Mon Apr 16, 2012 7:47 am

The Linux Console Font Size … 8x14 is apparently an alternative


any text on it, in console mode, would be sufficiently legible! (as it defaults to an 8x8 matrix


zfh10
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Re: Portable display for Rasberry Pi

Mon Apr 16, 2012 7:51 am

for many people, what is viewable in console mode will be irrelevant, as a GUI will be the main mode of use I would say...

Phil Spiegel
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Re: Portable display for Rasberry Pi

Mon Apr 16, 2012 8:05 am

I have no knowledge of what font size adjustment is available in Linux GUI's - I'm a RISC OS user where I can have anti-aliased fonts of any size I like.

However,  for many a small screen application, its likely to be an 'embedded system' - and needs starting up, if not all input in 'console'/terminal mode - provided it can be read.   It maybe that for ones eyesight's sake, a larger monitor needs to be attached during genral development! - but for my planned uses, the start up and any operational messaging will be on small screens - to fit in with '1:22' scale model railways.

Having the ability to eliminate colour subcarrier burst, to generate a monochrome display would be a great advantage - but this does not appear in the Config file as an option.

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jojopi
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Re: Portable display for Rasberry Pi

Mon Apr 16, 2012 8:13 am

Phil Spiegel said:


The Linux Console Font Size … 8x14 is apparently an alternative


The Linux console on a framebuffer device uses whichever font you chose when compiling the kernel, but the default is 8x16.  (This is until the distribution loads a font from disk, if it is configured to do so.)

It is very clear from the character aspect ratio in Liam's video that the default font on the Pi is not 8x8.

arm2
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Re: Portable display for Rasberry Pi

Mon Apr 16, 2012 8:19 pm

jojopi said:


Phil Spiegel said:


The Linux Console Font Size … 8x14 is apparently an alternative


The Linux console on a framebuffer device uses whichever font you chose when compiling the kernel, but the default is 8x16.  (This is until the distribution loads a font from disk, if it is configured to do so.)

It is very clear from the character aspect ratio in Liam's video that the default font on the Pi is not 8x8.


When using a fixed width bitmap font they often are taller than wide (Descenders are part of the reason) but twice as high as wide sounds wrong. The other thing is some screens are rendered as non square pixels. I'm not a Linux user so don't know what is normal on linux. Like Phil I'm interested in the composite output which is often 640x256 or 640x240 i.e. no square pixels.

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