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

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Your "guess" at the end... regarding commercial vs. hobby... like anything I do, "that depends". The impetus, as usual, is for my own hobby application. But I've had reasonable success in this world on the principle that "I'm nothing special". No, that's not a self-confidence issue that my mother has to worry about... its a business mantra that suggests if I have a need for something... so do others. Its virtually impossible to be unique in this world. The market may not be large (a relative term if there ever was one) but in my ventures so far, I've found them to be "large enough".

Take the two examples I touched on earlier:

1) An automotive cruise control. I bought a car. It happened to be a rather quirky car, but has its cult-like following. For whatever reason, it isn't offered with cruise control - either standard or as an option. I wanted cruise control. To my surprise, none of the existing aftermarket cruise products (costing $80 to $300) would work because of the particular way this car operates (100% drive by wire - getting more common). That meant the cruise control had to actually communicate with the car's computer to work rather than doing it the traditional mechanical way because the "gas pedal" was really a large potentiometer so there was no direct (or indirect) linkage between the pedal and the engine. What did I know about cruise controls? Nothing. What did I know about cars? Next to nothing. But I learned. My first tip came from a common product called a ScanGauge that plugs into any newer car's OBD port and reads all sorts of data. Right there I knew it was possible, at least, to get the necessary information from the car (speed, throttle position, etc). I learned that this car used CANBUS as its network. What did I know about CANBUS? Nothing. But I learned. So from that I determined I'd need some sort of "microchip"... and I put that in quotes for a good reason... at this point, I had no idea "Microchip" was a brand. That's how little I knew about ANY of this. But I learned. And it so happened, that the PIC was a good way to go. I studied datasheets (up until this point I never knew there was such a thing) and I got the general gist of it. I was going to do it all myself, as funds were very limited, and I searched for some sort of device to hook into my car to read the CANBUS data. I found a sub-$100 unit and contacted the small company that made it with a bunch of questions. Keying in on my novice-ness, he offered to help. For a very reasonable sum, he designed the hardware on this and I focused on the firmware and getting all the data from the car. What did I know about firmware? Nothing. But I learned. I learned C+ from scratch (had some experience in Perl and php programming) and spent a lot of time with my ICD2's help file :) I spent DAYS watching the screen of my laptop with hex numbers flying by a million lines a minute as it took in the raw data from the car, which I had to manually decode (absolutely no manufacturer support or documentation). What did I know about hex? Nothing. I learned. I had no wiring diagram for the car... but that's not rocket science. Anything I didn't know, I learned. What kind of a market is there for a cruise control specific to ONE quirky car?? NOT BLOODY MUCH! But that's the definition of "niche", now isn't it. I made 1000 of those units and so far I've sold 800 in a little over 2 years. @ 1000 units, they cost me $70 each to make and, as I mentioned before, that INCLUDES the cost of buying the car, paying the hardware guy, all PCB production and assembly, AND injection moulds for two plastic parts (people told me those would be $40k... I ended up getting them for $3.3k), custom (nice!) packaging - boxes and plastic inserts - very professional, all components and printed manuals. Everything but my own time. I sell them for $500 each and have not discounted any of them except for a few promotional cases... do the math.

2) An EL inverter backlight circuit. I'm not going to go into nearly the detail ("thank god", I know). But similar thing... it started as a requirement for ME. I fly model airplanes and the radio I chose doesn't have a backlit LCD. Its a popular radio and "I'm nothing special" so if I want it, others want it. And I found tons of people that did it... using cheap crappy inverters already on the market along with EL panels that they had to trim to size. And those cheap inverters are NOISY and HUGE and relatively power hungry. This time I did all the hardware myself. I found an IC specifically for driving EL panels far more efficiently than the simple inverter setup, so I went to work... reading, and learning, and doing. This project isn't nearly as profitable, but that's the nature of things sometimes. Its a $60 radio, so people are willing to pay hundreds for an add-on :) Still, I make them for about $15 a piece (500 at a time) and sell them for $40 and so far, so good.



My point is this: commercial possibilities are everywhere. Much of it starts with the confidence of knowing it CAN be done (you just have to find a way) and just because you don't know how to do something doesn't mean you can't LEARN!
 
So I just found this one. Other than the fact the resolution is too low in this particular chip (I'm searching for other versions), is that not the kind of things I want in general?

Techwell’s TW8807 LCD display processor is a low cost high quality TFT panel controller with an embedded NTSC/PAL/SECAM TV decoder, scaler, de-interlacer and timing controller. It is designed to support analog panels used in video applications including portable TV, rear seat car display, and portable DVD.

The TW8807 contains all the logic required to convert standard TV signals to the digital control and data signals required to drive various TFT panel types. It supports TFT panel resolutions up to WQVGA (480x234) with 1-pixel/clock formats.

The chip accepts CVBS (composite) analog input or S-video analog input for use as a video monitor. Up to four physical CVBS inputs or one S-video input can be connected.
 
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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 were discontinued long ago (pre 95), so are either terribly hard to find, OR very expensive.

One of the classic chips was the TDA3562 - which was purely analogue (as all were back then) - sources of them now would be as spare parts, obviously they won't have been manufactured for a LONG time. For hobbiest use, an obvious source would be to get one from an old TV, which would also supply you the required delay lines and crystal etc.
I suspect the module you speak of contained a number of IC's to support the decoder, as well as analogue.

It might have had one or perhaps two other IC's, certainly there was nothing complicated about it. I'll try and think where it might be? :D
 
The TW8807, from the flyer, looks like a great chip! Any lucky sourcing it? And 480 x 234 isn't too bad, certainly DVD quality on a 7" tft from a couple feet away. These are OK quality, but only 320x240:

**broken link removed**

And nigel, from a purely geeky point of view, I'd love to see a snap of the PCB of that decoder :D
 
Yes, sourcing it shouldn't be too much trouble... once the company is back online ;) Just my luck... Techwell was recently purchased by Intersil, and they're going through some growing pains by the sounds of it. I tried all the numbers and emails at Techwell I could find and was getting no responses when I read a press release about the acquisition by Intersil. I contacted someone there that assured me the part numbers are current and production is continuing... just that they haven't finished the transition yet. Her "guess" from looking at whatever she had to look at, was that for 1000 pcs they'd be in the $2 range.

One good thing, possibly, about the acquisition... is that Intersil has a very good sales engineering support team and she said they'd be able to provide "loads of sample schematics".

But really, who knows? At this point its a product that isn't effectively available.

Oh, and the 480 x 234 limitation (which won't work for my purposes) is just that one chip. They have a whole TW88XX series that run the gamut.
 
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So thats a one chip solution? well, at least for the conversion and LCD controller :)

I don't want to bring back the old 'it is available' thing again, but it really is:

Amazon.com: PYLE PLHR76 7-Inch Widescreen TFT/LCD Video Monitor with Headrest Shroud: Electronics

Headrest displays for cars, CCTV security systems, baby monitors, portable tv's - all of these use TFT LCD's (some CSTN, but mainly TFT) with composite video in at a reasonable cost of between $45 and $99 US. Amazon came up with around 50 results. Whilst they may not be easy to find just by searching for 'composite video TFT' - by application, they are everywhere.

From what I have read about the techwell chips (digikey sells quite a number of their IC's) they are an OEM replacement for what once was the field of ASIC's. They do exactly the same job, but are available outside of a single company :D As such, I'm thinking they would require the same support circuitry, although perhaps its a more integrated solution.

Out of interest, what resolution were you after? VGA? or SVGA?
 
VGA is what the broadcast source is.

The higher end chips are available on Digikey... I somehow missed them. $9 and up for volume. Of course they need a host of support circuitry to work... but I think we're just talking about typical resistors, caps, etc. Since it has a built-in MCU, all logic is done on-board. I'm going to order one up and buy that $30 wal-mart photo frame and see what I can do. But first I'm going to continue to study the data sheets.
 
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