[sdiy] Using digital photoframes as a source of cheap graphic LCD screens

[Eric Brombaugh]

Tom Wiltshire wrote:
> This is synth-diy, but only just, so my apologies if this seems rather 
> off-topic.
> 
> I've bought a few LCD character displays for use in my synth projects 
> (and the first one to use one is now nearing completion) but I've also 
> wondered about using graphic LCD displays. The problem with these is the 
> cost.
> 
> However, digital photo frames are now commonplace and cheap. 7" frames 
> go on eBay for £20 - try buying a 7" graphic LCD for that much money!
> 
> So my question is; Does anyone know of any sites (hackaday or 
> instructables or such like) that have opened one of these up and worked 
> out how to interface to it, or does anyone know a good reason why this 
> isn't a good idea?

Interesting idea. I've seen a few teardowns on these things and there's 
really not much to them - some sort of big processor/SoC (usually an ARM 
of some sort, with USB & LCD drive built in), an SD memory slot, power 
supply and user interface. The biggest problem is that the LCD drive 
logic is entirely subsumed in the processor, and the processor is mask 
programmed / OTP so you can't easily reflash it with your own code to 
take over the display. Another issue is that there are literally 
thousands of different models/mfgs of these picture frames out there and 
there's a lot of churn in the marketplace, so getting a reliable supply 
of them one you've done the reverse engineering may be a challenge.

I did a bit of fooling around with the old Mattel JuiceBox toy a while 
back (http://elinux.org/JuiceBox). Overstock.com was blowing them out at 
6 for $25 a few years ago and I picked some up. They've got a Samsung 
ARM with audio, ADC, LCD drive, serial port & 8MB or 32MB of SDRAM. The 
firmware is in an OTP ROM, but some enterprising hackers have figured 
out how to jam their own code into the SDRAM from an external flash at 
startup and there have been apps that use the LCD as a graphic display 
driven from the serial port.

I've seen references to some ebay sales of reasonable-size (QVGA) 
embeddable color LCD screens - usually in the $30 range. Typically these 
need to be refreshed though, so you'd have to find a processor with the 
drive logic to handle that (building your own would be prohibitive) so 
the complexity starts to run away.

There is a pretty nifty little Arduino 'shield' available with a color 
OLED display and touch screen interface.

http://www.liquidware.com/shop/show/TS/TouchShield+Stealth

That's certainly hackable and could be used with other processors.

Eric