Mini LCD screen

[chrimeg]

Just wondering if anyone has done this outside the PSONE screens as of yet.

I've notice 5", 4" etc picture frame LCD screens now going for around $15.00.

Has anyone ever interfaced these types of screens into their cabinets as a secondary monitor to display controls etc.

I've been thinking of this for quite a bit of time now as they have gotten so cheap. Just can't seem to find a way to interface them.

Anyone have an idea on how to do this or where to find hacks for these style screens. I'd assume its just an interface to convert SVGA/S-VIDEO/RGB onto the mini LCD.

[Beretta]

dunno.. i'd say it probably varies from model to model.

it's a neat idea if someone gets it right, i would'nt except to see s-video in one.. perhaps vga but im sure it wont be as simple as opening it up and finding a vga connector.

or it could use something proprietary .. im just speculating here.

[Blanka]

Forget the picture frames. They are hard to adapt to moving images. I've seen a portable-PS2 pack on eBay for 39 euros, with a case and a 5 inch LCD screen for the PS2 image. Guess that one eats composite or S-video.

[MonMotha]

Most of those small LCD screens have a totally non-standard interface (as far as anything you'll see).  It's typically parallel digital RGB data clocked at some rate with some synchronization signals (hsync, vsync, den, pclk, and sometimes some others for no apparent reason).  Every once in a while you'll fine one that wants parallel RGB with embedded sync/SAV/EAV ala BT.656.  Some accept 4:2:2 YCbCr for some strange reason.

Some of the larger panels (mostly intended for laptop usage) accept LVDS at 7x clock on 3,4, or sometimes 5 pairs plus the LVDS clock generally (but not always) at the pixel clock rate.

Connectors are almost always a 0.5mm pitch (or sometimes smaller!) flat flex cable.  Not the easiest thing to interface with mechanically, and you certainly don't have parallel digital RGB floating around anywhere, anyway.

Some devices have a board that accepts analog inputs (either RGB, YPbPr, Y/C or composite), digitizes it, formats it for the panel, and spits it back out.  Those are handy if you find a model with such a board as interfacing is easy, but generally display quality is iffy at best due to poor quality scalers.

[chrimeg]

I remember a post somewhere where a person took an old phone LCD and interfaced it to display images from the computer like a second screen. He eventually modded it into a mouse and it would display slide show images when connected to the computer.

I'd love to be able to interface a small LCD sceen into my bezel that would show game controls once a game is selected or being played.

I'll see if I can relocate that link and post it at some point. Meanwhile if anyone else has ideas on how to do this please post how you plan/done or trying to do it.

[Encryptor]

chrimeg

I found this link. It look like they hacked a key chain digital photo frame to play video.

http://spritesmods.com/?art=picframe


Encryptor

[chrimeg]

I've also located the link for hacking a mini lcd screen into a mouse.

Looks very promising.

Hopefully someone with an electronics background can also come up with solutions.

The last link that was sent also looks like a very good hack. Unfortunately it only runs on linux right now.

Here is the link I found: http://metku.net/index.html?path=mods/loginoki/index_eng

[MonMotha]

The really tiny LCDs for cell phones are generally SPI interfaced (including the one you linked).  They often have little to no timing requirements other than a maximum frame rate.  You may be able to get acceptable performance by bit-banging SPI off a parallel port.  Don't expect more than maybe 2-5FPS doing this, but it may be acceptable for your usage.  If you need something faster, there's lots of uCs out there with USB interfaces and SPI masters.  These will let you run the LCD pretty much as fast as it can be run.  You can buy bare LCDs of this nature from Sparkfun in single quantity.

Some higher end small panels, especially in QVGA size, are so-called "smart panels".  These have a framebuffer on them, so you don't have to constantly scan in video data like you would to a conventional monitor.  You can do random access to them as you please.  Again, this could be hooked up to a parallel port (esp. in EPP mode) fairly easily with just some "glue logic" (74 series or a small PLD) or again a USB enabled uC with a local bus and some suitable firmware.

Most LCDs in picture frames and such are standard dumb LCDs that need to be constantly scanned.  For this, you need a framebuffer which means RAM.  Your parallel port probably can't run fast enough for VGA (best you can really pull on a modern PC is usually about a 10MHz cycle rate in SPP mode) to keep up with the required pixel clock, so you'd need some external hardware for that, but you may be able to manage QVGA with a lot of CPU overhead.  The hardware isn't complicated (some RAM and a small CPLD will do to glue it to a parallel port), but it isn't going to be "plug and play" to a PC.  Again, a small uC, some RAM, and a PLD to handle the LCD interface wouldn't be too expensive, but might be a fair bit of design work for a one-off application.  I've done something similar before on an FPGA.

[Ginsu Victim]

I had to stop reading that because I was starting to feel more and more dumb as I went along...

[MonMotha]

Heh.  I do this stuff for a living

If you want something hackable, take a look at portable DVD players.  Many of them are nothing more than set-top DVD player system-on-chips paired with a slim DVD reader and an LCD with a daughterboard to accept S-Video or composite from the system on chip (since that's all they often output).  Pretty easy to hook up to: apply power and analog video.  Quality is usually kinda bleh, though.  The scalers and such aren't really designed for graphics and text but rather the "softer" edges of TV and movies.

[Ginsu Victim]

Heh.  I do this stuff for a living

I was aware, but it still didn't do much for my ego.

[chrimeg]

All sounds good although the electronics talk is a little over my head

Anyhow I found a link that would seem to do exactly what I'm talking about.

http://www.extremeoverclocking.com/reviews/misc/5in_LCD_Video_Module_1.html

Only I can't find the screen as they are discontinued by parts express and I don't have model numbers etc to source the part.

The portable DVD hack above sounds promising but how would you determine the connections when pulled apart unless it has external S-Video/VGA/RCA jacks?

[Bender]

I'm working on something similar right now
since you don't need the DVD player you can get used ones really cheap on eBay
seems that the DVD readers in those portable go all the time
I picked up a 9" $25

I have a question though.
There is a composite line in but the DVD defaults to the DVD player and I want it to go directly to the Line-in
Is there a way to connect the composite directly to the LCD?

If not, is there some way to send a delayed button press (to select Line-in) that I could hook up to the power button?
I'd need a delay of about 3 sec.

[Organic Jerk]

I just noticed a post on Engagdet for USB monitors that may be perfect for this thread...

http://www.engadget.com/2009/09/30/doublesight-debuts-trio-of-new-smart-usb-monitors/

http://www.doublesight.com/product/?idx=55



A 7" USB Monitor ...hrm

[Beretta]

7 inch might work.. i would'nt go larger then this, really a something between 3-5 inch would probably work well if you just wanna display button layout.