EricMiddleton
Posts: 47
Joined: Wed Jan 18, 2012 3:47 am

Re: Touch Screen LCD

Sun Jan 22, 2012 4:04 am

Also, does the LCD just use the standard LVDS link and what kind of plug is it?

Themroc
Posts: 44
Joined: Fri Jan 06, 2012 9:35 am

Re: Touch Screen LCD

Sun Jan 22, 2012 7:53 pm

Dave Seeber said:


Some peopel mentioned getting component LCD screens from China-

After some research, I found this:

http://hk-rmt.en.made-in-china.....V-GPS.html

and I contacted manufacturers for a price quote:

For 50 pcs of A035QN02 V9, unit price is US$12.8 ( Ex-works, no tax).
We have 5K stock and you can pay us by Paypal / Western Union / TT to our company account.
 
Best regards,
 
Richard Yang 
--------------------------------------------------------------------
HONGKONG RMT ELECTRONICS CO., LTD.
I think this is the cheapest price mentioned so far, but IMO the real difficulty would be connecting it- would it need software or a d/a converter... stuff like that?

Yeah, the price sounds good and


Minimum Order:  5 Pieces


also. What i don't like about it is that it seems to need the usual dotclock, hsync and vsync signals but only has 8 data inputs (instead of 24). No idea if those DSI to RGB chips can cope with that. If not, some additional multiplexers would be needed.

Eric Middleton said:


Thanks for all the help; I'll call them on Monday. Quick question about the digitizer though. Can you point me in the direction of some information about it's interface? I know how the four-pin resistive panels work, but the iPhone digitizer uses projected capacitance, which I am not familiar with.


U're welcome! I've learned a lot investigating this... Sry, i seem to know even less than you about touchscreens. But tomorrow i will look for a chip.

Eric Middleton said:


Also, does the LCD just use the standard LVDS link and what kind of plug is it?


As i just found out, this suggests it's MIPI DSI Thus, no stinkin' BGA converter chips are needed. But the datasheets wouldn't hurt nevertheless This http://www.airaccent.com/repla.....22318.html seems to be the needed connector.

EricMiddleton
Posts: 47
Joined: Wed Jan 18, 2012 3:47 am

Re: Touch Screen LCD

Mon Jan 23, 2012 1:53 am

Thank you everyone for all the help. I have started a new topic here: http://www.raspberrypi.org/for.....topic=2316 where I will discuss all the aspects of the PDAs I am making. I want to make it easier for people to make things like this by putting all of the information into one area. Special thanks to Themroc especially for all the help.

Eric

funny
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Joined: Mon Jan 16, 2012 11:14 am

Re: Touch Screen LCD

Tue Jan 24, 2012 11:21 am

Good work from all of you. Feeling lucky to read the posts under this thread.

JustinN
Posts: 6
Joined: Tue Jan 24, 2012 11:57 am

Re: Touch Screen LCD

Tue Jan 24, 2012 12:07 pm

Having done a bit of playing around with touchscreens before, I can offer this bit of advise.

Before you buy ANY screen, regardless of how cheap it may be, ask to see the datasheet first! I got some amazing little screens that were dirt cheap, however to my dismay, I could not power them with directly from my ARM11 chips, as they simply did not have the processing power to handle what the screen needed. The solution was to purchase a controller cheap, which acted as an interface between my MCU and the actual display. After all of this, it worked out cheaper to just guy a different display with a better interface which allowed me to push data to it more efficiently and allowed me to tell it to keep images on the display without having to constantly telling it every millisecond what it should be doing.

I can recommend the Sony PSP displays, as many people in the Hackerspace community have had a lot of success with them, and as a result there is a lot of people who can lend you support with writing your drivers.

- Justin

Mattylad
Posts: 98
Joined: Tue Jan 17, 2012 9:59 pm

Re: Touch Screen LCD

Wed Jan 25, 2012 9:24 pm

What about something like http://www.dealextreme.com/p/r.....h-4-105378 for £15 from the Ipod touch?

Themroc
Posts: 44
Joined: Fri Jan 06, 2012 9:35 am

Re: Touch Screen LCD

Sat Jan 28, 2012 9:46 pm

Mattylad said:


What about something like http://www.dealextreme.com/p/r.....h-4-105378 for £15 from the Ipod touch?



For us$ 15, this looks very good indeed, even if it"s probably just a display without a touch digitizer. The "touch" and the iphone have a lot in common, not just the look. Even the LCD connectors appear identical:

http://www.lunacommerce.com/15.....-flex.html

http://img.dxcdn.com/productim.....5378_3.jpg

And since the iphone 3gs and 4g both use MIPI DSI, there"s a very good chance that also the "touch" 3 and 4 do. Thus, the r-pi should be able to drive their LCDs directly, without any converter chips. I have just ordered one, plus the (hopefully) fitting connector.

Edit: This might be an even sweeter deal:

US $12,79 for a 4" 800x345 ultra-wide-screen including cap. digitizer:

http://www.ebay.de/itm/LCD-Dis.....4aafee0f1a

Unfortunately, they only ship to the US, others can get it here (for $17.73):

http://www.aliexpress.com/snap.....16744.html

This one has RGB/TTL inputs, thus it needs a converter chip. See http://www.cpkb.org/wiki/LG_BL.....ice_manual

EricMiddleton
Posts: 47
Joined: Wed Jan 18, 2012 3:47 am

Re: Touch Screen LCD

Sun Jan 29, 2012 5:34 am

Are you certain that that datasheet for the iphone4 is accurate? Also, do the drivers exist for the DSI connector yet? I'm aware that the GPU covers that, and since the GPU is proprietary, I don't want to have any surprises when I try to make these things.

EricMiddleton
Posts: 47
Joined: Wed Jan 18, 2012 3:47 am

Re: Touch Screen LCD

Sun Jan 29, 2012 5:51 am

Cheapest iPhone 4 screen: http://www.ebay.com/itm/Repair.....818wt_1396

They are beautiful, 960x640, >300ppi. If they will work, they would really class up the project I'm working on.

Themroc
Posts: 44
Joined: Fri Jan 06, 2012 9:35 am

Re: Touch Screen LCD

Sun Jan 29, 2012 9:19 pm

Eric Middleton said:


Are you certain that that datasheet for the iphone4 is accurate? Also, do the drivers exist for the DSI connector yet? I'm aware that the GPU covers that, and since the GPU is proprietary, I don't want to have any surprises when I try to make these things.


No, not absolutely certain, but it looks like it could be the real thing and i doubt anyone would fake 30 pages of curcuit drawings. This is no top secret DEW kinda stuff, it's just a cellphone...

And if DSI would not be usable, i believe Gert would have told us here:

http://www.raspberrypi.org/for.....#post29877

scarfy
Posts: 11
Joined: Mon Jan 23, 2012 8:42 pm

Re: Touch Screen LCD

Sun Jan 29, 2012 10:04 pm

A Question....

I found a  7" touchscreen for friendlyarm (Mini/Micro2440, Mini/Tiny6410 boards) http://www.andahammer.com/s7/...

but i don't know if is possible to conect it to rPI.... does anybody know ???

PS. found datasheet for this 7" touchscreen http://www.friendlyarm.net/dl......70TN83.pdf

Themroc
Posts: 44
Joined: Fri Jan 06, 2012 9:35 am

Re: Touch Screen LCD

Mon Jan 30, 2012 10:40 am

Scarfy said:


A Question....

I found a  7" touchscreen for friendlyarm (Mini/Micro2440, Mini/Tiny6410 boards) http://www.andahammer.com/s7/...

but i don't know if is possible to conect it to rPI.... does anybody know ???

PS. found datasheet for this 7" touchscreen http://www.friendlyarm.net/dl......70TN83.pdf


This is like the 1st one in this thread, it needs RGB/TTL. Possible, but a converter chip is requiered. The cheapest one that may work i found so far is this:

http://avnetexpress.avnet.com/.....me_VSE-T11

It's max. resolution of 1280×1024 should be sufficient for a 7" screen.

Shteve0
Posts: 3
Joined: Mon Jan 30, 2012 1:49 pm

Re: Touch Screen LCD

Mon Jan 30, 2012 2:02 pm

Wait! I know literally nothing about this stuff (hello, by the way, and apologies for bringing down the IQ average in the room), it's exciting me nonetheless.

If ipod touch/iphone replacement screens might work, and you fine chaps seemed fairly positive about the prospect above, could I conceivably get an ipad screen to function?  Would that entail a digitizer too?  Would it need external power, and how would I go about it?

Basically hoping a touchscreen/RPi/laptop speakers combo - running xbmc and wired to the network - may offer me an awesome jukebox option for my lounge/kitchen/bedroom/bathroom/dungeon/servant's-quarters/evil-twin-brother's-cage needs. I'd need a casing for it, but I'll need one for the RPi too, so what the hey.

Cheers in advance!

S

PS: I can't find a datasheet, sorry.  I did look though, I promise

PPS: I'd probably use reinforced glass for the one in my evil twin brother's cage.  I'm new here, but I'm not stupid

Themroc
Posts: 44
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Re: Touch Screen LCD

Tue Jan 31, 2012 5:00 pm

Shteve0 said:


If ipod touch/iphone replacement screens might work, and you fine chaps seemed fairly positive about the prospect above, could I conceivably get an ipad screen to function?  Would that entail a digitizer too?  Would it need external power, and how would I go about it?

[...]

PS: I can't find a datasheet, sorry.  I did look though, I promise


I couldn't find a datasheet either, but since i also couldn't find a cheap replacement panel for the 'pad, i didn't try too hard… 7-inchers in general seem to be outrageously expensive right now. All gone to these nice folks i guess.

Digitizers are usually separate items.

An LCD panel does need power, it's your choice how you supply it.

riderred
Posts: 10
Joined: Fri Feb 03, 2012 1:56 pm

Re: Touch Screen LCD

Fri Feb 03, 2012 2:32 pm

Does any one know how much TC358764 DSI to LVDS controllers are in modest quantities and where you can buy them from?

Same question for STMPE812A touchscreen controllers?

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abishur
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Re: Touch Screen LCD

Fri Feb 03, 2012 3:17 pm

I've done a lot of searching on the first one, I haven't been able to find any place that keeps them in stock but the price I've seen is in the 4 dollar range per unit (sorry no guess about bulk ordering prices)
Dear forum: Play nice ;-)

specsdude
Posts: 52
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Location: In a small English village, far from the eyes of Mordor

Re: Touch Screen LCD

Sat Feb 04, 2012 7:49 pm

I have been supplied with a datasheet for the afore-mentioned screen:

http://hk-rmt.en.made-in-china.....V-GPS.html

The PDF:

https://mail.google.com/mail/u/1/?ui=2& ... sp=safe&zw

Unfortunately I'm not acquainted with electronic specifications, so it doesn't make much sense to me, can anyone else verify if this screen does or does not use DSI?

Thanks, hope this helps
Arise! Arise, riders of Théoden! Spears shall be shaken, shields shall be splintered - a sword day, a red day, ere the sun rises! Ride now! Ride now! Ride! Ride to ruin, and the world's ending! Forth Éorlingas!

Themroc
Posts: 44
Joined: Fri Jan 06, 2012 9:35 am

Re: Touch Screen LCD

Sat Feb 04, 2012 10:09 pm

Dave Seeber said:


I have been supplied with a datasheet for the afore-mentioned screen:

http://hk-rmt.en.made-in-china.....V-GPS.html

The PDF:

https://mail.google.com/mail/u/1/?ui=2& ... sp=safe&zw

Unfortunately I'm not acquainted with electronic specifications, so it doesn't make much sense to me, can anyone else verify if this screen does or does not use DSI?

Thanks, hope this helps


That link doesn't work for me, but this datasheet for A035QN02 V9 says it uses a rather unusual 8 bit interface. Which translates to "no DSI" plus there's no one-chip-converter that i'm aware of.

Piw32
Posts: 82
Joined: Sun Dec 04, 2011 8:46 am

Re: Touch Screen LCD

Mon Feb 13, 2012 3:52 am

Why not use a small FPGA to do the DSI to LVDS conversion ?

riderred
Posts: 10
Joined: Fri Feb 03, 2012 1:56 pm

Re: Touch Screen LCD

Mon Feb 13, 2012 9:00 am

After a bit of research the only way I can see of building a Pi to LVDS interface board is described here http://e2e.ti.com/cfs-filesyst.....n-Note.doc

It uses two TI chips TFP401A and SN75LVDS83B, noth of which are available in low quantities on Farnell.  The chips costs £7.83+£5.08 going down to £4.40 +£ 3.09 in quantity.  This is pretty expensive relative to the $25 board cost.  Anybody got a cheaper/better solution.  FPGA sounds great, but I would not have a clue where to start.

Themroc
Posts: 44
Joined: Fri Jan 06, 2012 9:35 am

Re: Touch Screen LCD

Mon Feb 13, 2012 8:32 pm

Piw32 said:


Why not use a small FPGA to do the DSI to LVDS conversion ?


'Cause the DSI spec is kind of top secret:


Specifications are available to MIPI members only.


So, someone would have to found some company (a cheap Ltd. would probably do), join MIPI, apply for discounted membership dues (


Member companies with revenue (including all of its affiliates) of less than $250 million per year (based upon the member’s most recently available fiscal year financial statement as of the date of application for new members, or as of 31 October for existing members) are eligible for a 50% discount on annual membership dues.


), pay them $4000, download&leak that stinkin' spec and then we could look which FPGA can do the job…

The easier route seems to be HDMI or DVI, as their specs are open to everybody:
http://www.ddwg.org/lib/dvi_10.pdf
http://www.evernew.com.tw/HDMI.....ion13a.pdf

Also, they have a standard way to tell r-pi the required timing and resolution information for the attached monitor or panel. Apparently DSI lacks that, so the foundation or broadcom would have to provide a setup tool for the GPU. Someone (JamesH, IIRC) wrote that this will possibly come sometime after release.

Piw32
Posts: 82
Joined: Sun Dec 04, 2011 8:46 am

Re: Touch Screen LCD

Mon Feb 13, 2012 10:13 pm

Is it legal to hook up a logic analyser to the DSI lines and figure out what is happening ?

Microsoft wasnt much worried when the Kinnect got hacked...

roli
Posts: 13
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Contact: Website

Re: Touch Screen LCD

Tue Feb 14, 2012 10:54 am

But do you actually need to know how the protocol works? Well you need if you wan't to build a converter, but you proabably don't if you have a display and a device that both support DSI?

I realy want a small (around 4") display for one of my projects and the iphone display looks like a realy good choice. So does anyone know if it will actually work? I have been reading a lot of speculations in this topic but there were no definite answers.

Oh and if anyone is interested, here is the datasheet for the LCD from the iPad. I don't know anything about it, just found the datasheet. And it is a good resolution display for the 60$ price.

http://www.displayalliance.com.....2-SLAA.pdf

clockwork
Posts: 1
Joined: Thu Feb 16, 2012 12:21 am

Re: Touch Screen LCD

Thu Feb 16, 2012 12:40 am

Hello you suave and intelligent gentlemen and ladies.

I am in the same situation as roli. I would love to be able to get an ipod/iphone display for my project, as its the perfect size, and they really are nice screens.

I was surprised to find that the screens use DSI, and also surprised by how cheap they were.

I was wondering if anyone had specs on the displays, especially what kind of power they would need, etc. I am fairly new with displays as well, and i was hopping to use teh RPi to break myself into them. If its as simple as apply connections, apply power, I would be amazed. I know that there will probably have to be some driver stuff that goes into it as well, but that seems fine.

Could someone else comment as to the viability of using the I-screens as displays?

I realize that its rather hard to do so without the actual device to test with, but another opinion would be helpful.

Thanks,

Clockwork

Themroc
Posts: 44
Joined: Fri Jan 06, 2012 9:35 am

Re: Touch Screen LCD

Thu Feb 16, 2012 8:40 pm

clockwork said:

I was wondering if anyone had specs on the displays, especially what kind of power they would need, etc.
Ipod touch 3G:

http://www.beyondinfinite.com/.....1-FD01.pdf

For the Phones, i haven't found no datasheet yet, just this


Remarks : for Apple iPhone 4G

Input Voltage for Panel : 5.672/1.8V

Total Power Consumption : 560mW (Max.)


and here, on pg. 16 you'll find the connector pinout.

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