thedo
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Re: Portable screens that dont cost an arm and a leg

Mon Jan 23, 2012 8:34 am

I've been watching the Raspberry Pi story unfold with great interest and like many people intend to buy one to try to help bring back some fun to my coding time. I've been looking into purchasing a small 5-10" screen that I can use on the device, so I can keep it all-in-one where appropriate and break out the wires to full blown devices when I need to.

Given the low cost of many Android devices I didnt expect this to be a big deal - a 10" touchscreen Android with a decent hires screen can be had for £100 -  £150.

However looking to buy a standalone screen of similar spec I'm looking at £200+ (Lilliput seems to have this market sewn up!). Which seems a tad excessive for a $25ish device, and when you can buy a complete Android system for half that price......

Ebay has a wide selection of replacement laptop screens, however (to an electrical newb) it's difficult to know what to look for. Obviously they dont provide hdmi/composite inputs, but I'm guessing it must be possible to figure out how to hook something like this up? But where to start?

Has anyone else had a look into this area? Would you care to share your findings/musings? I had a look on the wiki at the RPI screens section (the bit at the bottom about interfacing with LCD screens), but it's not something I know enough about to be able to digest without help :S

kasperl
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Re: Portable screens that dont cost an arm and a leg

Mon Jan 23, 2012 9:05 am

There's quite a few people working on a cheap HDMI->LVDS converter to use old laptop screens from the HDMI port. For a cheap solution first you might want to try a mobile phone screen on the DSI port, but there hasn't been much word on what is and what isn't going to work, AFAIK. I would love a DSI->LVDS converter myself, but only Toshiba seems to be making the right chip, and they're not selling that at small quantities I think.

scologic
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Re: Portable screens that dont cost an arm and a leg

Wed Feb 01, 2012 11:43 pm

One of the LVDS issues that hasnt been addessed is the cable costs. Having dealings with LVDS cable makers in the UK the tooling cost for the crimping machines that make the cables push small 1's and 2's of LVDS cables into the £30 - £50 bracket. LVDS also suffers from no common pinout between interfaces and also display panels.. Sorry I couldnt bring better news..

super-6-1
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Re: Portable screens that dont cost an arm and a leg

Thu Feb 02, 2012 1:52 am

I have been looking into this because i maybe building a small back pack computer so what i have some to find for cheap is this.

http://www.amazon.com/MIMO-UM-.....038;sr=8-2

it may seem pricy but the issue here is the only way to do what we want is to ether wait for a RPi laptop to come out or get what we need. Im just sad it doesn't come with more USB ports or even a PS/2 port for that matter. But again this is being made for development and nothing else really.... which is why the community is getting it first.

JoeDaStudd
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Re: Portable screens that dont cost an arm and a leg

Thu Feb 02, 2012 10:58 am

You'd be better off buying a cheap HDMI screen then modding it.

You have to remember the R-Pi in its current state doesn't come with a case, won't be be pretty once its being used (due to the cables) and there isn't a off the shelf power pack for the R-Pi. So you'll be modding/adding to the R-Pi a fair bit from the start.

WereCatf
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Re: Portable screens that dont cost an arm and a leg

Thu Feb 02, 2012 11:20 am

JoeDaStudd said:


You'd be better off buying a cheap HDMI screen then modding it.


Well, he did say he plans to use it as a backpack computer, I atleast am not aware of any small enough HDMI-enabled screens. Of course if there was such it would most likely be the best route forward, but as I said, I am only aware of desktop-size and larger screens that sport HDMI-ports and they're usually terribly expensive.

Garacesh
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Re: Portable screens that dont cost an arm and a leg

Thu Feb 02, 2012 12:15 pm

I, too, have been wondering about this.

With touch-screen Android devices with 4" ish screens selling for £150ish I would have though small screens would have been somewhat on the cheap side. Guess not D:

I see a lot of people rabbitting about 7"+ screens but personally I'm looking for 3"-4" because I want to making it small and portable. Unfortunately I have the electrical know-how equivilent to a cat's knowledge of what isn't supposed to be a bed. Safe to say I'm looking for something I can plug in and use - but have no idea where to get something like that from.

D:

hippy
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Re: Portable screens that dont cost an arm and a leg

Thu Feb 02, 2012 12:40 pm

thedo said:

Given the low cost of many Android devices I didnt expect this to be a big deal - a 10" touchscreen Android with a decent hires screen can be had for £100 -  £150. 
Manufacturers have the advantages of economy of scale.

The R-Pi has a display interface so hopefully one day there will be a cheap, small, high quality LCD which is 'connect and go' but that's not here at present. In the meantime it's a case of trying to find a suitable HDMI monitor or HDMI-to-LVDS setup which does the job. Unfortunately neither easy to find nor cheap and, due to the low cost of the R-Pi, will likely always feel expensive in comparison.

I have recently been playing with in-car DVD player monitors which take composite video. Unfortunately mostly low resolution and nowhere near as good as most digital picture frames nor tablets but that seems the cheapest option available at the moment, especially if bought second hand. Okay for general images and large font displays but will have to wait for an actual R-Pi to see if the composite out can be tweaked to improve things.

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rurwin
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Re: Portable screens that dont cost an arm and a leg

Thu Feb 02, 2012 12:41 pm

With 3 or 4 inch screens, you can forget about HDMI -- it's going to make very little difference.

This is the best I found: 640x480 3.5 inch, free camera £39

Most of them have resolutions around 480x300

This is the search I used: "4 monitor av"

pjt
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Re: Portable screens that dont cost an arm and a leg

Thu Feb 02, 2012 12:45 pm

Using a Kindle seems a good idea as a screen for a portable Rpi.

Kindle doesn't need any hardware changes and still works as a  Kindle.

Mentioned in thread http://www.raspberrypi.org/forum/projec ... th-the-rpi

But so far no comments - any opinions?

ejames
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Re: Portable screens that dont cost an arm and a leg

Thu Feb 02, 2012 1:23 pm

There are a lot of small screens out there, some with touch capability.

E.g. look at http://www.coolcomponents.co.u.....Path=45_71#

The problem is that the interface to these tend to be SPI or I2C or a standard serial connection, so there would need to be some major driver writing to get them to appear to linux as a standard output device. Not beyond the realms of possibility though. I'm sure this sort of thing is what the community would love to get it's teeth into.

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grumpyoldgit
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Re: Portable screens that dont cost an arm and a leg

Thu Feb 02, 2012 1:24 pm

The Kindle uses E-ink technology and are monochrome. I suspect they would be more of a problem to set up than a cheap android tablet. My Storage Options Scroll has an HDMI output socket but not an input socket so I don't see that these could easily be used as screens for the Pi, without taking them apart.

ejames
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Re: Portable screens that dont cost an arm and a leg

Thu Feb 02, 2012 1:28 pm

I bought a uLCD-32PT 3.2 inch LCD display to connect to my Arduino. Seems to work nicely. If I could get my hands on a PI I could have a crack at getting it to work with one of those....

hippy
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Re: Portable screens that dont cost an arm and a leg

Thu Feb 02, 2012 1:36 pm

It really depends if one is just after a screen or wanting an integrated screen, for example in an R-Pi based tablet.

Any device with the right connectivity and software should be usable with the R-Pi as a VNC-style client, and you can probably get something suitable like an old laptop for free or low cost, or use a tablet or an eBook reader. A USB-to-VGA adapter is another solution.

Those provide display capabilities but it's getting lowest power, minimal hardware and maximum capability of a directly connected display which is hard to solve at low cost at present.

JoeDaStudd
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Re: Portable screens that dont cost an arm and a leg

Thu Feb 02, 2012 2:17 pm

Sorry my mind is mush today.

I was thinking of the LCD screens similar to what ejames linked while looking at prices of small RCA screens. Damn I need to sleep.

Again sorry for my mistake.

Garacesh
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Re: Portable screens that dont cost an arm and a leg

Thu Feb 02, 2012 2:18 pm

ejames said:


There are a lot of small screens out there, some with touch capability.

E.g. look at http://www.coolcomponents.co.u.....Path=45_71#

*snip*


Actually, after seeing Nintendo DS screens, I'm wondering, would those possibly be compatible? (or easily converted?)

pb
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Re: Portable screens that dont cost an arm and a leg

Thu Feb 02, 2012 3:59 pm

what about the screen of an ipod? Actually I still got an Ipod Touch 2g and it's not used at all. I found a picture of the connector of the lcd : ClickMe Can anyboy tell me what kind of connector that is? It's not the biggest, but I guess it would work for some

Thanks

Themroc
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Re: Portable screens that dont cost an arm and a leg

Thu Feb 02, 2012 4:06 pm

There are many possible ways to plug LCD panels into the r-pi, but unfortunately most require converter chips (like that DSI -> LVDS mentionend above). Others are

DSI -> TTL/RGB

HDMI -> LVDS

HDMI -> TTL/RGB

The needed chips are


expensive
only available in a 0.1 mm pitch BGA package
hard to get
unusable without a datasheet, which is some kind of f*ing state secret

or any combination thereof. So not much fun there

That leaves the solutions w/o the need for any converters, like panels with MIPI DSI input.  Major drawback is: very little choice, but since the iPhone 3gs and 4g (and probably the 4gs as well as the iPod touch 3 and 4) use it, at least the 3.5"ers are ubiquitous and cheap.

Or panels with composite input. Much more choice, but usually low-res (they're meant for car rear view or cheap pocket TVs).

Or finally one of the 2 panels with DVI (= HDMI without sound). Not exactly "small" though...

george.endrulat
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Re: Portable screens that dont cost an arm and a leg

Thu Feb 02, 2012 4:40 pm

I'm sure it might be not what we're after but a simple search on Alibaba: http://www.alibaba.com/showroo.....nitor.html for 10 inch hdmi lcd monitor turned up quite a few.

If we could narrow down one that fills most of our requirements I'd be more than happy to go in with a large group to get a bulk discount or even on items that require minimum quantity purchases.  I'm sure if they do work with RP we can sell them individually to the RP community.

What I'd be looking for in a panel/monitor:

Resolution: 800x480 minimum

Size: 7" to 13"

Weight: minimal

Power draw: minimal

Thickness: minimal

Has a RP compatible touchscreen that works with that particular size panel

Clair
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Re: Portable screens that dont cost an arm and a leg

Thu Feb 02, 2012 5:19 pm

Reading this entire thread, I may be off in la-la land here, but isn't the R-Pi supposed to work with a television? If so what about a cheap, small TV? I know it's way bigger than a cell screen, but hey, won't it work? I'm most interested in getting up and running as fast as possible. If I can commandeer the small TV in the kitchen, I'm going to do it!

JustThisGuy
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Re: Portable screens that dont cost an arm and a leg

Thu Feb 02, 2012 7:28 pm

As I'm looking to be using my Pi as a carry along I've looked at lots of screens. One portable TV with HDMI input is here http://www.amazon.com/Axion-AX.....7TZT0O8PGI

I've purchased, however a AAXA P1 Jr Pico projector: http://www.amazon.com/gp/produ.....00_details (Note: the the small selector control, a 4 direction joystick, on my first one failed after minimal use. They replaced it but I'd watch out, the thing feels a bit non-robust)

The throw (distance between the lens and the screen) is kinda long so it's kinda problematic for the bus. I'm putting together a fold-up screen/stand to carry along for sit down locations like the bar. Not really a great solution but one I can deal with until something better comes along.

I'm looking at a screen reader (TTS) and running in console mode as much as possible for the music playing end of mine.
Any conversation about a sufficiently complex subject is indistinguishable from babble.

Garacesh
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Re: Portable screens that dont cost an arm and a leg

Fri Feb 03, 2012 11:24 am

Projector instead of a monitor.. did NOT think of that..

I think I'd have to use a powered USB hub, though I'm guessing said projector would need to pull its power through USB, and the idea of an on-screen keyboard would be moot if there wasn't an actual screen xD So that's Projector, Keyboard and Mouse wanting USB.

If I go down this route, though, I can't make the Pi 100% portable D: I want it completely non-reliant on mains sockets, if I can.

Unless there's Keyboard+Mouse combos in 1 USB port? Probably is, now that I come to think of it.. TO GOOGLE!

Deedee
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Re: Portable screens that dont cost an arm and a leg

Fri Feb 03, 2012 1:14 pm

Hi, my first post, though i have been reading the forums ....

I hope this dose not come across as a rant, as i don't mean it that way at all, just an impassioned plee/question

Isn't the real point of a portable screen that's cheap is for the kids?

I keep seeing prices of £100 or more mentioned.

I'm know just enough about electronics to make a transistor to turn on an LED, so I'm coming from an ignorance point of view here.

I remember back in 1979 or 80 some one in my school had a Science of Cambridge Mk14 with a tiny LED 9 character display running on a pp9 battery. That's what started my interest in computers. I remember when my farther asked me if i would like to go on holiday to Spain for Christmas or have a ZX80.... you can guess what i chose.

Far more important to find a way, any way of taking a cheap screen from any commonly available device that an average 12 year old with maybe a little help from a parent or teacher can adapt to "mod the Pi". There is a level of excitement with the Pi and a child, being able to sit and code (or play with it) in a class or bed room is one thing, but i guarantee the interest and excitement would jump a quantum level if the child could take it out in break time, the playground, where and when ever to show any one who will sit still for 10 seconds what they have done!

And like any heath Robinson device, i don't think they could care less if the screen was held in place by hot glue and duct tape with a bunch of wires, point is many kids would prefer that. " This is something "I" made".

I don't even think it would be a crime if there were only two buttons to control what they could see on the screen without any other input, in my humble opinion, its that fact they could take it out of their pocket and SHOW another child " Hey, you seen this?"

So who would care if it was the screen from a phone or a lap top or even controlling mice (the sort some little boys carry in a pocket and has the ability to make some scream and jump on a chair) to "paint" the output on the tarmac of the school playground. Its to stimulate them, and the best way of that is to use word of mouth, the kids themselves, the more this can be achieved the better.

So my question to all you wonderful electric techies out there is, what, of any screen, could be adapted to display any thing on the pi that can be picked up for a song and modified to work?

Is there any thing at all that could be used that a child could with help make to work AND that could be afforded out of pocket money?

Crack this question and the kids will do much of the work of the foundation for you, plus, you may end up with a Blue Peter Badge if you asked them nicely

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rurwin
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Re: Portable screens that dont cost an arm and a leg

Fri Feb 03, 2012 2:14 pm

This is your solution for under £50, just like it was back in the day.

That's certainly what I'll be doing.

ETA: This is an ideal time to pick up a second-hand television. There are large numbers floating about that are not capable of picking up freeview. We have three CRT TVs in the house that could be re-tasked to be RaspPi monitors, and one of them probably will be, but there are many LCD TVs on eBay going for a few pence, from two-inch screens all the way up to thirty-three inches.

zfh10
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Re: Portable screens that dont cost an arm and a leg

Tue Mar 20, 2012 4:39 pm

where are these 2-in screens you speak of?

I can only echo what others have said.  TVs are not what people want so much, but rather ways of hooking up small netbook or phone screens.  It sounds like it is possible.  Then we'll get to see real DIY skills from people learning about computing and electronics, as they build their own projects.

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