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Simple LCD with composite video in... what do I need to do?

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I've Googled all day and I apparently don't know what to search for.

I want to "make" a simple (cheap!) LCD monitor for viewing a composite video signal. I'd like to take a real cheap 8" digital photo frame from Wal-mart and use the LCD in it and get the signal to output onto that. What I can't find any info on (because I don't know what to search for) is what electronics are involved in taking the video signal from the source and putting it onto the screen.

Before you go and suggest I buy a this or a that instead... I've looked, and I can't find anything that is a) minimum 800x600, b) minimum 7", c) has composite video in. I've found tons of examples that get 2 out of 3, but none that do all three that are under $100. Wal-mart's got this 8" 800x600 for only $25 but its only a photo frame.

Thoughts? Thanks.
 
A photo frame is vastly different than showing moving video.

walmart is your friend:

$67 gets you:
Viore 7" Portable LCD HDTV:
o 7-inch active matrix TFT screen
o Built-in ATSC digital tuner
o User-friendly interface
o Closed captioning and V-chip support
o Automatic/manual scan
o Built-in stereo speakers
o Rechargeable lithium-ion battery
o Audio/video input
o Audio output
o USB port
o The Viore 7" Portable LCD HDTV has a miniSD memory card slot for playing digital media files
Viore Portable LCD TV 7" PLC7V96 - Walmart.com

$118 gets you:

Viore 13" 720p 60Hz LCD HDTV with AC/DC Adapter, LC13VH54:

* 16:10 LCD panel
With a 1280 x 800 HD resolution
* Wide 50-degree vertical and 90-degree horizontal angles
See a clear picture from anywhere in the room
* Built in ATSC digital/NTSC analog tuner
Watch conventional and digital broadcasts, including HDTV programs where available
* High brightness of 200cd/m2
Place your 13" Viore LCD HDTV anywhere
* 5,000:1 dynamic contrast ratio
* HDMI Inputs: 1
Enjoy a lossless HD experience with HDMI one cable experience
* 2 built-in speakers
Get great sound with these 3W speakers
* VGA port
Connect your PC to your 13" Viore LCD HDTV
* AC/DC operation with included AC power adapter and DC car adapter
13 Viore LCD HDTV, 720p - Walmart.com
 
Before you go and suggest I buy a this or a that instead...

I wrote that for a reason, and would very much rather have an answer to my question.

A photo frame is vastly different than showing moving video.
That doesn't tell me anything. Is the actual LCD display incapable of showing motion regardless of the electronics driving it? I kind of doubt that since my existing (smaller/older) frame shows motion all the time as it is transitioning between pics, and many newer frames can play mpeg off of USB. So my question was... what electronics are involved in getting the LCD stripped out of a photo frame to show analog composite video?
walmart is your friend:
Yes, it is... they have the cheap frame I'm looking at. Your suggestions do me no good, as they are not available to me. But even if they were... the first you suggested we have no idea what the resolution is and the second we have no idea if it has composite in (plus its over $100).
 
There are a bunch of in car DVD players, with the option of adding a second screen. You can pick up the option second screen, separately for around $30.

The difference between a monitor, and a picture frame, is that composite video is an analog signal, the picture frame displays digital. There is no reason for the picture frame to support an analog signal, so your project would be to basically gut the picture frame for simply an LCD, which might be pretty much useless, if you can't find a data sheet. You would still need to convert your analog video signal to digital, in a format the screen understands. The details are way beyond my knowledge and means, I just know that you need to do quite a bit quickly, and some heavy microcontroller programming (not even sure they are up to the task). And of course, you will need to be careful about part placement and layout, if you want relatively noise free video. These sort of devices are usually developed in a lab, by a team. Not saying it would be impossible, just not very practical or cost effective, which don't always matter.
 
The LCD's (mostly TFT's but some CSTN for the cheaper ones) used in digital photo frames and incar entertainment systems are quite simple to drive.... digitally. The require a horizontal sync, and vertical sync to tell the display drivers when to start a new frame, and when to start a new line. Also a single 'clock', which on a transiston reads digital inputs which control the brightness of each sub pixel (Red, green, and blue for each 'pixel'). These are usually 5/8-bit numbers.

Composite video is wildly different as its analogue. Boards which convert this to drive LCD's must do the following:

Extract the sync to work out when the composite signal contains cr/Yr info.
Convert the voltage to digital, using a high speed ADC (20Msps?)
Store these samples (which are the brightness of each pixel) in a buffer.
Generating timing signals for the LCD display, Hsync, and Vsync.
Take samples from buffer, convert from a single number to seperate R,G and B numbers.
Send to the LCD to 'draw' the pixels line by line.

It IS complicated, I have managed it (sort of) with a couple of CPLD's, and some parts robbed form a PSone LCD display. And, to be fair, to buy one pre-made IS a lot cheaper, and easier. But most of the above can be done with a simple IC, containing all the necessary buffers and ADC's. It won't be the cheapest chip ($9?) but will do the job when coujpled with a small microcontroller to program its registers for settings.

Video Decoders | Analog to Digital Converters | Analog Devices


That said, it doesn't have to be expensive! A PSone LCD isn't a TFT, it is in fact a CSTN (colour STN LCD) and so its contrast isn't great, nor is its quality... but composite video was deisgned for PAL/NTSC anyway, which isn't the best resoluiton in the world. It has built in speakers, and can happily take in standard composite video/audio, and display it without trouble. These go on ebay for anywhere from $10 to $25 US.

As someone mentioned 'in car displays' I have several of these, also from ebay. There were 'ripped' frmo a car so they aren't nicely housed, but all that was needed was soldering a phono plug connection to the PCB, and it displayed PAL OR NSTC. Also has a nice I2C interface to change aspect ratio, refreshrate, contrast, and brightness (all digitally).

Usually both the above displays are not really 'manufactured/designed' by the manufacturer. In fact, generally the circuitry used to drive the display from composite video is part of the display itself (all on the same PCB on the back of the LCD, which it is mounted on). So you CAN buy displays that take in analogue and display it, as OEM, not consumer products.

Examples?
https://www.electro-tech-online.com/custompdfs/2010/09/LTE072T-4408.pdf
LM072QCAT50 (can't find the datasheet lol)

I think OKI semiconductor produced quite a number of chipsets designed for this, most likely superceded by single chip solutions.

Blueteeth
 
A useful answer :) Thank you Blueteeth.

Considering this is an electronics forum, I'm rather shocked at the prevailing "don't make it - buy it" attitude. If the IC - by far the most expensive part - is "not cheap" at $9... then there's no way the components are going to add up to the $120 to buy an almost-good-enough TV from Walmart. Bottom line... if what I wanted existed at a low enough price, I'd buy it. But it doesn't. Or at least I'm not going to do a $100+ a pop trial-and-error to find out if it does or doesn't.

I'll look into a 2nd screen for in-car DVD - I hadn't thought of that, thank you. I did find one portable DVD + 2nd screen from WalMart and that second screen would have sufficed, but I wasn't willing to spend the $170 for the DVD player I didn't need just to get it.

I still think converting a picture frame to what I want is feasible... I just thought I could get more help on how to do it. I think its obvious it can be done: The screen can already handle mpeg video, so its not a physical limitation of the LCD itself. The cheap LCD tvs do it, so its clearly possible to convert analog to digital. So its that ADC circuitry that I'm after, as expressed by Blueteeth. I was certain that by Google I could find a schematic somewhere... but to my surprise I found nothing. Not even a hint where to look next.

I ran into the same thing trying to make an EL inverter for an EL panel backlight. All I could find were ready-made piece-of-****-boxes from China. I asked people how to make them and I got the same kind of responses, "why not just by one?". You know how annoyingly unhelpful that kind of response is? I shouldn't have to express every single parameter and requirement of my idea to get an answer to a question. In that case, I had physical limitations due to the case it was going in, and NONE of the inverters on the market did the trick. Since there are tiny watches with EL backlights in them, obviously it was possible. But nobody would answer me or just say, "I don't know"... they'd all try to give me "advice" by telling me to buy this or that :) But in the end I did it. I eventually found an article discussing a (no longer available) IC EL driver and that gave me the tips for search terms and I finally found a current version and from that made the circuit in the necessary size.

I expect to eventually do the same here.
 
A useful answer :) Thank you Blueteeth.

Considering this is an electronics forum, I'm rather shocked at the prevailing "don't make it - buy it" attitude. If the IC - by far the most expensive part - is "not cheap" at $9... then there's no way the components are going to add up to the $120 to buy an almost-good-enough TV from Walmart. Bottom line... if what I wanted existed at a low enough price, I'd buy it. But it doesn't. Or at least I'm not going to do a $100+ a pop trial-and-error to find out if it does or doesn't.

There's no way you can just buy a $9 IC to do what you want - it's a LOT more complicated than that.

If you were wanting to make 100,000 units it becomes more cost effective, but presumably you only want the one? - and I would expect it to cost well in the hundreds of dollars, and many months of time.

You didn't find anything, because it's FAR more complicated than you think - and been able to display MPEG video really has no bearing on it whatsoever - it's not just a question of converting analogue to digital.
 
I think you're wrong. Of course its not just a matter of buying a $9 IC, using some duct tape to attach it, pray to the 'letronics gods and hope it works. Circuitry is involved (duh)... but beyond the $9 IC (and I'd be really surprised if I couldn't get away with a $4 one) is likely just like any other electronics project... a handful of cheap components put together in the proper way and voila. I'm not saying its "simple" as in conceptually simple... but I'm sure it is "simple" as far as the electronics goes. And there's absolutely no way it'll cost hundreds of dollars. Even for one.

"but presumably you only want one" - yeah, that's what this forum appears to be full of... presumptions ;)

The fact that it can display MPEG *REALLY DOES* have bearing on it Nigel... because that proves beyond a doubt that there is nothing about the LCD module itself that is incapable of displaying motion. That's critical. If it can display video OF ANY KIND then it must be capable of doing what I want. OF COURSE NOT BY ITSELF. It seems like you think I have some delusions that I can just take my yellow plug from my input, shove it directly through the surface of the screen (since there's no input) and expect video to magically appear. In other words, you assume I'm an idiot. I'm not. I just am not familiar in AD conversion and that's why I posted here.

But now my biggest question becomes this: If you don't know the answer and can't provide tips... why not post, "Gee, I don't know" or just don't post at all?


There is an answer. The fact you don't know what it is doesn't change that.
 
Well, perhaps the '$9' figure I posted was misleading. Yes, you can buy a single IC which is designed to convert composite video to 24-bit digital colour, with adjustable sync timing. It can extract the colour and brightness, (and the sync) from standard composite video...which is essentially a composite to RGB converter - and then sample this with high speed ADC's. But these require a hell of a lot of support circuitry, PCB layout concerns, power requirements, filtering... trust me, what seems to be a great $50 project, can balloon into the point of diminshing returns.

Some numbers for the math masochists (like myself):
The framerate of TFT/LCD displays is in the order of 50-70Hz, and if you used a 'dumb' display (just one with drivers, no controller, by far the msot common) then you must 'draw' each frame, providing 3 x 8-bit numbers for each pixel. For say 320x240, thats 74800 pixels. multiply that by 3 bytes, and thats 225kbytes (230400 bytes). You must send this ammount of information for every frame, whether the display is static, or a motion picture. for 50 frames per second, you're talking giving the display 10.98Mbytes per second.

Now, if you're just displaying data from a microcontroller, with a bit of logic, and some ram to store your frame, its possible. But our source is a constantly changing waveform - you can't go back and re-read what the signal once was. So in order to allow for the differences in timing between composite video, and what the LCD wants, one needs a buffer. The video decoder takes in composite video, and spits out bytes, it must be stored in ram, so that your LCD controller can take that information when it needs it. This equates to more IC's, more circuitry to generate the timing signals = mo money ;)

The resolution of your LCD determines how many pixels you need per line, and as such, determines how the composite video is sampled. It starts to get VERY hairy when working out the sampling frequency, and timing requirements to determine when each part of the circuit does what. Get samples, store in buffer, new LCD line, read from buffer etc..

All of these parts, although relatively straight forward, add up do a rather complicated system which is rarely done by DIY'ers, although FPGA's are usually used in such situations.

If you open up a cheap in-car display (not a tv, as that has RF and tuning as well....gah) you will see some pretty big chips, generally a few ones from well known manufacturers (like those analog video decoders) as well as a master controller, which I think is generally an ASIC only available to the maker of the glass/TFT. Much cheaper for them to use custom jobs.

If I get time tomorrow I'll take a few snaps of the PCB's of such displays just to show you what you're up against :)

Apologies for another long post, but I might as well mention 'mpeg'. Mpeg video, since its all digital, can generally be handled entirely on one chip with very little support circuitry (read: analogue). So whilst a digital photoframe will read MPEG's, decode them into 'bitmap streams'....it passes this directly to the LCD. This means the part that 'controls' the LCD is embedded in that MPEG decoder chip (again, another ASIC which is unlikely you'll ever find the datasheet for). So all you get from a digital photoframe, is the LCD display glas, and its driver chips (on the display itself) which you can probably get for around $20 anyway.

Modern embedded electronics has become far more integrated, what once required 10 chips and a shed load of analogue, is often now just a single IC with a handful of passives. There are very few 'modules' circuits. This makes things smaller, and cheaper, great for consumers, but a ***** for us guys who like to salvage parts and subcircuits, or hack consumer goods for our own projects :(
 
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I bought a 13" LCD tv today from Wal-mart that won't suit my needs, but I wanted to see what kind of circuitry is involved. You guys are blowing it way out of proportion I think. The vast majority of this TV's circuitry (in terms of physical quantity) is converting the 120V ac to the 12v and 5v dc the "guts" require. The next biggest amount of circuitry appears dedicated to handling the myriad of inputs (HDMI, RGB, Component, Composite, Coax, USB). They all funnel into a series of 3 ICs. I'll have to get out a magnifying glass to identify them as I just can't read the lettering on them... the only thing I can make out is that one of them is by Micrel (oddly enough... same IC maker that made the EL driver I mentioned above).

If things were as complicated as you all are making them out to be... tv's like this wouldn't exist. Yeah, yeah... I know... they're making them by the tens or hundreds of thousands...


Anyway, clearly I'm fighting a losing battle here. I thought I could get assistance from people that might know some answers. I'll try somewhere else.

Thanks Blueteeth for being as helpful as you could be.
 
I bought a 13" LCD tv today from Wal-mart that won't suit my needs, but I wanted to see what kind of circuitry is involved. You guys are blowing it way out of proportion I think. The vast majority of this TV's circuitry (in terms of physical quantity) is converting the 120V ac to the 12v and 5v dc the "guts" require.

The PSU is by far the simplest part of the set :D

The next biggest amount of circuitry appears dedicated to handling the myriad of inputs (HDMI, RGB, Component, Composite, Coax, USB). They all funnel into a series of 3 ICs. I'll have to get out a magnifying glass to identify them as I just can't read the lettering on them... the only thing I can make out is that one of them is by Micrel (oddly enough... same IC maker that made the EL driver I mentioned above).

If things were as complicated as you all are making them out to be... tv's like this wouldn't exist. Yeah, yeah... I know... they're making them by the tens or hundreds of thousands...

Large custom IC's, huge development budgets - it's all a question of scale - the chips probably aren't even available to you.

Anyway, clearly I'm fighting a losing battle here. I thought I could get assistance from people that might know some answers. I'll try somewhere else.

You'll get the same answers elsewhere - it's not a viable project.

If you really want to play with it?, try something like the BT848, which is the chip commonly used on PC capture cards - perhaps something like that and an ARM processor could be astarting point for a few months or years of development?.
 
blah blah... [i don't know]... blah blah


I got the same useless answers on my EL backlight project.


Your first comment makes my own point, genius. I was exemplifying that the majority of circuitry is spent on something very simple. The rest was all done on a couple of ICs along with a bunch of standard passive components.

Your second comment hardly makes any sense at all. The chinese typically make these cheap consumer products based off datasheet schematics. The ICs are hardly going to be custom made.

Your third comment... I get the same answers OVER AND OVER, not because its not a viable project, but because people like you insist on commenting just for the sake of commenting ONCE AGAIN... if you don't know the answer, then why post?


Ridiculously unhelpful.


We developed an electronic cruise control for a drive-by-wire vehicle a couple years ago after having to trudge through crap threads and "expert" opinions telling us it would costs "hundreds of thousands of dollars" and "years of development" (because we were lacking support such as schematics and wiring diagrams from the car manufacturer)... we got it done all-in for $70k INCLUDING $28k to buy the car... and it took under 9 months.



Point? I get sick of the "don't bother... can't do it" attitude. YOU can't do it, then that's fine. Don't tell me I can't.
 
If you've got $70K to throw at a project it's an entirely different matter :p

But as you're obviously so clever, why are you asking in forums for something you consider a simple matter?.
 
I never said it was a simple matter. YOU are the one making a boat load of presumptions and doing so yet again.

I'm asking because I know there are people out there that can point me in the right direction. People out there that know a lot more about it than I do... and clearly you're not that person. And that's fine - I don't expect you to know everything. So why can't you just leave it alone and let someone post that might know something about it???
 
Calm down lads :)

I understand wanting to build something, perhaps from 'scratch', or more practically just building something with parts available to you - be they IC's, modules, or prebuilt consumer goods that can be modified. It's pretty much what the 'hobby' part of my electronics is! (work is a different matter, deadlines, where time is money). It is not only rewarding, but also very interesting, breaking down a 'problem' into serperate area's and working on each individually, then plugging it all together, debugging and tweaking.

I believe Nigel is pointing out the reason why you haven't found much information on this, albeit put in a rather blunt way (its his way, don't take it personally!). Perhaps it seems discouraging, but think about it, what answer do you expect? I could write well over a thousand words explaining what I know about such systems (the basics), and provide many diagrams but it would flood the topic. I could not find many links that may be of interest to you, except large datasheets for LSI silicon which would only tell you what that chip can do, not necessarily how it works - as it expects the reader to have an advanced level of knowledge to begin with. (a few I've read gave me a nose bleed). Also, these IC's are not designed to output to an LCD directly, requiring heavy digital processing from a computer (scaling, digital mathematics that would make an ARM9 poo itself).

Also note, I believe Nigel is a seasoned TV/video guy. He really knows his stuff, perhaps not the ultra modern digital implimentations of video systems (no offence nigel :D ) but certainly everything 'analogue', ie: composite video. And THAT will be your biggest hurdle in this project, decoding the input signal. It is why you have recieved so many discouraging answers.

In fact, if I was to build such a project for my own use, a single prototype (not commercial) I would agree that it would be MUCH cheaper and easier to implement a system to read AVI files from a hardisk, decode, and play them on a TFT. That is all digital, as such, there are many devices which can do the bulk of the work for you.

You mentioned there were only a few IC's in the TV you purchased. That is somewhat misleading, because what those IC's do is frankly incredible. And yes, they almost always are custom ASIC's, as its much cheaper to mass produce with ASIC's than buying multiple devices from other manufacturers and plugging them together. You can have almost everything on one chip, leaving the only external components being passives (large caps which dont' fit on-chip), power supplies, and commectors. The reaons 'most of the circuitry' in your TV was the power supply is because... its a power supply. Higher currents than the mA/uA found in IC's requiring larger components to disapate heat. You cannot integrate medium current power supplies inside silicon, it must be done with many larger individual components, giving the illusion that it is more complicated.

I have an old LCD display that takes in RGB + compsite sync. It has a seperate PCB which decodes composite PAL to RGB (not a trivial task...). I'll take a photo this afternoon and post it because, unlike ultra modern displays, this one has seperate chips for each purpose. (video amps, buffers, ADC's, field FIFO memories for each colour, as well as a controller). Its a great way to show the different stages your project will need. I'll take another photo of a newer one for comparison, which has most of the above systems on one chip. And you can check out the part numbers too! Because for the most part, they are made by the same manufacturer as the display (custom IC). Never sold outside of the company.

If you're still interested in this (not too discouraged), please state in simple terms what you would like to achieve. Basic outline, then some specifics :) I am no expert, but it is how I learn, and I will try my best to point you in the right direction. You never know, may find an IC which can take the sting out of it, or even make each stage yourself!

Blueteeth
 
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I have an old LCD display that takes in RGB + compsite sync. It has a seperate PCB which decodes composite PAL to RGB (not a trivial task...).

Actually, that's a pretty easy task - there are loads of different easy to use decoder chips that do almost all of it for you. I've even got a ready made unit at home that does it. If you remember the old Amiga computers, and the original picture 'scanners' for them, you used a B&W video camera to scan a colour image three times, with a different colour filter in front of the camera each time.

A small company a few years later made decoder boxes for them, which took a composite video signal (a still frame) and used a colour TV decoder chip to split it to the separate red, blue and green signals. I've no idea where it is now?, but I suspect it's in the attic somewhere.
 
Blueteeth... you continue to be helpful, even if you didn't mean to be :)

You ask me "what I expected" from posting here. "expect" is a strong word... its sort of like with my wife... if I "expect" some... hmm... special service... there's no bloody way I'm getting any, but there's no harm in "hoping" ;) I posted because Google wasn't getting me anywhere for once. I tackle a lot of projects and problems I don't know anything about, and in this case I figured I just knew so little that i didn't know what terms to use. "Get composite signal onto LCD screen" was amazingly fruitless. So I *hoped* that by asking it here in English to humans (rather than guessing what a robot wants to see), I'd get pointed in the right direction. You can tell from my first post that I fully expected the typical really-not-all-that-helpful-post-a-response-because-I-like-to-see-myself-post responses, and I did in fact get those. One always does. But I also figured I'd get a few tasty useful tidbits thrown in there, and thanks to you... I have.

I feel I'm halfway there now (in understanding, certainly not implementation) and its thanks to you bringing up the term "decoder". That was the "aha" term that's immensely helped my searching. There are plenty of ICs that are relatively inexpensive that are MRU's with built-in NTSC decoders AND LCD drivers. Those datasheets will be a great start I think.

I still don't think its going to be a fraction as difficult as you guys think it is going to be. And I also think its many magnitudes more difficult then YOU GUYS think I think it is :) Its probably going to be about as difficult as I expect... which is difficult, but possible.

As far as expense goes... I always look at that in a few ways. First, I need one for my purposes so I look at that "one-off" cost and I hope for one of two things. Either: a), its cheap and I make one for myself and that's that, or; b) its too expensive for a one-off. The latter is almost as good as the former... sometimes much much better. Because then its no longer a "one-off", but a "prototype". Because if it really is that expensive to make one, and we KNOW FOR A FACT its not that expensive to make many (otherwise we wouldn't have TVs at all)... then I can produce them for others in my shoes and not have to worry about the DIY folks crashing my sales. If its in between... that's where there's trouble, because its too expensive to make on for myself but not expensive enough that I can provide a cost advantage to others vs. DIY.

I've brought several electronics products to market and they all have this in common: 1) at the start, I knew next to nothing about what was involved; 2) its always cheaper and easier than it first appears; 3) there's always people on the Internet that should know a lot more than I do saying it can't be done; and 4) its intended for a very niche market. That's my niche... selling to niches ;) Always has been the case, always will be.




The reason I want to do the photo frame is because whether its a one-off or a prototype, Wall-mart's 800 x 600 8" photo frame for $30 is so far and away cheaper than any LCD I can buy from Digi-key. I've never done any project with an LCD and after searching the "big guys" I do have to wonder... where does one get cheap LCD's from? I mean when you're buying 1000 at a time. All components are expensive when you buy one, and dirt cheap when you buy millions... but there's usually a good source (like digi-key, mouser, newark, etc) for a reasonable in-between in the 1000's. I've yet to find that for LCD screens.
 
Actually, that's a pretty easy task - there are loads of different easy to use decoder chips that do almost all of it for you...../ /...A small company a few years later made decoder boxes for them, which took a composite video signal (a still frame) and used a colour TV decoder chip to split it to the separate red, blue and green signals. I've no idea where it is now?, but I suspect it's in the attic somewhere.

Whilst I believe that, I haven't found any IC's available to me which do this in analogue - that is, do NOT super sample the input signal and use DSP. The only part numbers I have found wwere discontinued long ago (pre 95), so are either terribly hard to find, OR very expensive. I have seen the small 'modules' which do this, but they are expensive and defeats the point of DIY :) (but with MUCH less of a headache). Googling reveals plenty of ENcoder IC's, but no analogue decoders. I suspect the module you speak of contained a number of IC's to support the decoder, as well as analogue. Only 'source' I have found is an old VCR which had 'scart out' (which just so happen to implement RGB as well as composite). That has a TDA-something large skinny dip chip, 64 pins I think.

I think I have been spoiled by the latest craze in single chip solutions, and I freely admit I do not fully understand standard analogue video signals just the basics, so knocking something up myself scares me. The people who created the PAL/NTSC standards must have been geniuses... encoding lots of different information (sync, colour, brightness) in ONE 6Mhz band signal, whilst still allowing TV's to decode it.
 
As for my source.... I must confess...Ebay. 'Spares/Repair', and bits 'n' bobs that take up space, people just want rid. Occasionally you'll find a gem, like a transflective 3.5" TFT, VGA resolution, composite vid in, for £6.70.

I WILL agree that, buying a digital photoframe, and robbing it of its display, is much cheaper than buying an OEM display. A car satnav can be brought for £60 which has all manner of goodies inside, the display itself is probably £70+ from farnell/RS/digikey. But for your proejct that just gives you the display, the glass and its drivers. Having an application, then sourcing the parts required, it can work out cheap and dandy to 'hack'. But don't let the parts you have available to you determine your application :) Often creates a lot more work for yourself.

That said, I often do that lol, its a great way to learn, even if it can be frustrating, requiring far more effort than expected. SMD adapters, high quality PCB's to be manufactured (either professionally or at home), prototype modules for each sub-circuit, debugging with an oscilloscope - and thats just hardware. Software for chips is another can of worms. Compilers, IDE's, programmers, In circuit debuggers, learning the code, AND how a processor implements that code. The list goes on, and it hasn't been unusual for my own projects to be 'off and on' for years.

But I'll make this the last post about 'plausability' and whether its worth it, I think its been covered VERY well so far by all concerned. And I guess this is for your own interest and hobby as opposed to any form of commercial application. So let the idea's flow people!
 
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