Camera converter

Forum for discussion of narrow-bandwidth mechanical television

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Camera converter

Postby kareno » Mon Mar 21, 2011 7:55 pm

Here's a preview of my latest 'one PIC wonder' - a 625-to-NBTV converter.
Attachments
Camera converter.wmv
Camera converter featuring Patrick Star
(2.18 MiB) Downloaded 939 times
kareno
 

Postby holtzman » Mon Mar 21, 2011 8:24 pm

Very cute, I still need a PC to convert camera signal to NBTV :wink: . What kind of camera do you use with converter? How long is the delay - with PC it's quite long.
And - what about your monitor? The image looks very good but can you show your televisor outlook?
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Postby kareno » Mon Mar 21, 2011 8:38 pm

Hi Holtzman,

My camera is a normal 625 line camera module that was liberated from a cctv security camera. And yes, it is instant - no pixel is more than 20msec old!

My monitor is my own design. It's interesting bit is the 8 inch disk that I made using OHP transparencies (hence the good raster). I won't say any more because both the camera converter and OHP disk are articles in the next newsletter, and I don't want to steal thunder.
Attachments
Monitor.jpg
My monitor using OHP disk
Monitor.jpg (36.39 KiB) Viewed 10920 times
kareno
 

Postby Steve Anderson » Mon Mar 21, 2011 8:46 pm

Hey Karen,

Seems you've beaten me to it! I was wondering if you were going to do a complement to the NBTV-625 device. My version, currently very incomplete, is also a 'One-PIC-wonder' but it does use another five small chips as support. As I mentioned elsewhere on this forum and in the newsletter, this number might grow but I'm hoping not.

Progress on this 625-NBTV converter has come to a standstill for the past two weeks. I reached a point where I had an output from the converter and could view it on a scope, but I had no operational NBTV display. So I've had to build yet another! Since this forum started I perhaps have built five, I'm not sure, but once they get operational, documented, photographed and maybe published here or in the newsletter...they're doomed! No mercy.

If they see one hour of operational life I would be surprised. Their innards are plundered for parts, circuit boards consigned to the trash...and they don't even carry Donor Cards.

This display, I vow, will not be dismembered. It will be kept whole. This is not the first time I've been caught out lacking this rather essential piece of gear.

Back to the converter...

All being well the monitor should be good to go in a couple of days, this will allow viewing of 'whatever' it's output might be. It currently is not much more than a glorified test-card generator, reading its own RAM in the 'reverse-rotated' manner that the scan directions require.

The input filtering and clamping is done, all I've yet to do is marry up the sampling/writing to the reading/output...ONLY he says!

I may have some screen-shots by the weekend, then again, I may not.

Good video, mechanical display? It's a little hard to tell.

Steve A.

P.S. You've just answered my question...
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Postby kareno » Mon Mar 21, 2011 8:56 pm

Hi Steve,

The attraction of my converter is simple to make so (I hope) will appeal to people starting out in NBTV. But my converter is not state-of-the art - it's bandwidth is not as high as it could be so there is a place for a high performance multi-standard converter.
kareno
 

Postby Steve Anderson » Mon Mar 21, 2011 9:29 pm

Hmm, rapido reply!

I wouldn't call it 'State of the Art', perhaps "State of the Ark'. Like yourself I've tried to keep it as simple as possible yet without compromising too much in the process. The current version (I'll call MkI) is single-standard in, single-standard out, video is handled at 6-bits, partly due to the current lack of a suitable A-D...the AD7822s I ordered still haven't arrived! Having said that, 6-bits seems adequate for NBTV to a lot of folk.

The MkII version, should I ever get around to it, could well be a very different beast.

Interesting question regarding the PC processing delay, not having used PC-based software. Is the delay that long that lip-sync becomes a problem? That is the audio needs delaying a similar amount? Presumably this is not addressed?

Steve A.
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Postby AncientBrit » Tue Mar 22, 2011 6:48 pm

Karen,

I like the presentation of your monitor in a picture frame.

Never seen that done before.

And the use of OHP?
Sounds intriguing.

Regards,

Graham
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Postby kareno » Tue Mar 22, 2011 10:04 pm

Hi Graham,

Thank you. I have this disease where I walk around homeware stores and see project cabs where bread bins should be :)

I wanted the gubbins (now there's an old word) of my TV to be visible but protected behind glass. A box frame provided the answer. The stand is a towel rail, the tilting pivots are door stops.

What you can't see is the ABS box on the back with the motor, LEDs and electronics. That bolts to the hardboard insert of the frame so that the hardboard replaces the lid, if you see what I mean.

It's a great little TV but the synch is not good and it's a fight to get it locked. I think it needs electronic damping, but that's something for a future newsletter article.
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Postby AncientBrit » Thu Mar 24, 2011 6:52 pm

Karen,

I'm all for gubbins, there's too much sophistication these days!

Graham
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