NBTV without any moving parts. THE NIPTRIX

Forum for discussion of narrow-bandwidth mechanical television

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Postby gary » Wed Nov 21, 2012 8:16 pm

Albert, this IS Mount Everest (of NBTV anyway) ;-)

I think I may wait until the PCB version comes out.

(or a cheap 32x48 matrix module becomes available ;-)

Oh, and my version would HAVE to have a commutator (just kidding).

In 1986 I designed and built ON veroboard (what was I thinking? - oh well I was young and naive - about the same age as Julia Gillard was and she uses that excuse and gets away with it - so far) the attached schematic.

It was a kind of forerunner to todays MP3 player (but using continuosly variable slope delta modulation) intended to help disabled people communicate with their rehabilitation officers.

It worked - but eventually I needed the Universities logic analyser and/or storage cro to debug just a tiny little timing glitch in the serial to parallel converter. Otherwise it was kitchen table engineering. I looked this up because I thought I might have used 4017s somewhere but apparently not.

So I have an idea what you are going through Albert.

I have seen more complicated (NBTV even) circuits built on vero board but this is the most complicated circuit I have built using that technique. Other than the power supply this was built on one board. The RAM bus was a nightmare...

BTW this was drawn on an early version of autocad but I appear to have lost an electronic copy.

I attach a full copy of a HD image of the schematic in case anyone wants to peruse the circuit in detail.
Attachments
DSCI0001.JPG
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gary
 

Postby Viewmaster » Wed Nov 21, 2012 8:46 pm

Gary, I am continually gob struck by what NBTVers do and you have
gob, gob, gob struck me with that complex cct all on vero. :)

Have you any photos of it still? I'm sure many here would like to see this Vero colosuss.
Maybe a Vero museum should be launched on the net showing the best in ' Various Vero. "

I hereby declare Gary to be, "The Vero King."
“One small step for a man,"......because he has Arthritis.
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Postby gary » Wed Nov 21, 2012 9:29 pm

Alas no, I didn't have a camera in those days (believe it or not).

But I have now bought myself an Aldi digital camera (hence the pictures) so anything henceforth will be well doco'd LOL

I like to think of that board sitting on a shelf gathering dust somewhere - maybe not being used but not thrown away either.

To describe it, you can imagine the top of the board was quite well populated, but the wiring side was just solid copper wire, layer on layer. By the time I built this I was very experienced with complex wiring (there are still high speed trains running here in Oz (XPT) that I did most of the wiring for) and appreciated that it needed to be neat and well laid out to have any hope of debugging it. So it was something I would be proud to show - but...

In any case I am not sure that I would be the NBTV "Vero King" - I remember Pedro doing a 625 video to NBTV converter on it - I think Graham's circuits are often done on Vero - and if I am not mistaken MUCH of Steve Anderson's VALVE and transistor stuff is also done on it.

Mind you - doing the amount of RAM I did on Vero - well...

None-the-less I wish I had a photo of it :-(

I also wish I had KEPT a single photo (borrowed camera) of my very first NBTV camera/monitor built in circa 1968 - it got creased so I threw it away - stupid!
gary
 

Postby M3DVQ » Wed Nov 21, 2012 10:02 pm

Buses are always the worst part. It's not that they're difficult, just so hellishly tedious. I bought all the parts to assemble a discrete logic zx81 clone some time ago but only got halfway through wiring the address bus before realising that the wire I was using was too heavy and abandoning it.

I will get it done eventually now that I've discovered the wonders of solder side point to point wiring using enamelled wire... Trouble is I've used some of the logic chips for other projects in the meantime :)
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Postby gary » Wed Nov 21, 2012 10:13 pm

M3DVQ wrote:Buses are always the worst part. It's not that they're difficult, just so hellishly tedious.


Exactly. My board was also done before I discovered the (comparatively) delights of wire wrap. Of course these days with laser printers and computers I would probably do a PCB using hydrochloric acid and hydrogen peroxide as the etchant.

aaah 20-20 hindsight is a wondrous thing.
gary
 

Postby Viewmaster » Thu Nov 22, 2012 12:42 am

Here's my contribution to this Vero madness.
A three dimentional version :shock:

7 off 74150's stacked vertically so that all address pins/supply pins could be connected to the bus bars running down each side.....part of a PC controlled organ I built more years ago than I care to remember now.
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Postby gary » Thu Nov 22, 2012 9:55 am

Nice, that circumvents some wiring difficulties quite elegantly, well done!

Let's just hope we don't have to call on Paul Newman and Steve McQueen at power up. (A special null prize to the first to recognise that obscure reference ;-))
gary
 

Postby M3DVQ » Fri Nov 23, 2012 12:44 am

Towering inferno?
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Postby gary » Fri Nov 23, 2012 9:04 am

M3DVQ wrote:Towering inferno?


Spot on - here is your prize:

<null>


;-)
gary
 

Postby M3DVQ » Fri Nov 23, 2012 9:55 am

gary wrote:Spot on - here is your prize:

<null>


;-)


Thanks, I'll put it in /dev/null with all my others so it doesn't go missing
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Postby gary » Fri Nov 23, 2012 10:00 am

That's they way. Just don't go using it all at once - they are meant to be savoured...
gary
 

Postby gary » Fri Nov 23, 2012 10:02 am

Oh and BTW this particular version has no nasty smells or tastes, and is perfectly clear. Safe to use in any circumstance. Try one on your next BBQ - you are guaranteed to lose weight.
gary
 

Postby Viewmaster » Tue Dec 04, 2012 11:55 pm

Have decided to install all the NIPTRIX switching /control/power supply boards inside a transparent enclosure as shown here.
It will be wall mounted with the loudspeaker at the bottom.
In this way everyone can see my poor workmanship. :lol:
Attachments
NIPTRIX transparent enclosure.jpg
NIPTRIX enclosure
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Postby Viewmaster » Sun Dec 09, 2012 8:24 pm

I daresay that if Rommert is following this thread he will say, when viewing these pictures. "Been there, done that."

But others might like to see the LEDs starting to be soldered in.
Note black straw pieces on alternative LEDs for cross masking.

The neg connections all go to 32 vero strips for line clocking and the pos connections brought out to soldered cross wires for 48 pixel clocking.
I have now done 3 rows. (keeping up with your time schedule, Steve!)

Each row I found MUST be pushed hard against previous row with a straight piece of wood to ensure conformity in positions before soldering in.
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Postby gary » Sun Dec 09, 2012 10:13 pm

Nice work Albert, good luck with the rest.

The straw sections are not glued on right?

The only reason I ask is that when you first mention the "interference" between adjacent LEDS I thought hmmm well yeah. But now I wonder whether that would be a minus or a plus. The fact that adjacent LEDs would "glow" in sympathy with the "powered" LED might give a pleasant "softening" to the picture. Thoughts?
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