NBTV without any moving parts. THE NIPTRIX

Forum for discussion of narrow-bandwidth mechanical television

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Postby Steve Anderson » Tue Feb 12, 2013 1:31 pm

As you've identified the problem you may not be interested in this, but perhaps a good scrub-down of all the boards with an electronics-friendly solvent may help. Grease and fingerprints from during assembly can be quite conductive, especially on high humidity days.

The stray capacitance you're pretty much stuck with, one of Veroboard's traits. However, why only two rows (horizontals) display this is odd.

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Postby Viewmaster » Tue Feb 12, 2013 6:40 pm

Steve Anderson wrote:As you've identified the problem you may not be interested in this, but perhaps a good scrub-down of all the boards with an electronics-friendly solvent may help. Grease and fingerprints from during assembly can be quite conductive, especially on high humidity days.

The stray capacitance you're pretty much stuck with, one of Veroboard's traits. However, why only two rows (horizontals) display this is odd.

Steve A.


As you can see, Steve, the 80 transistors are really very close to each other. In this piccy it shows just 10 of the transistors soldered onto vero.

Maybe the two that had a problem had isolation track cuts so that adjacent copper is nearly shorted to give a leakage??? It is now all installed in its case so cannot see at present if this is so.
Anyway, as I said, by floating the trannies connections on those two the problem seems solved.
I might try a clean up as you suggested, but then it may disturb something else, so I shall ponder upon this.
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10 transistors.JPG
Transistors close together.
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Postby AncientBrit » Wed Feb 13, 2013 6:38 pm

Albert,

Never assume virgin Verotracks are isolated.

I once had a problem where two tracks had a high R between them. Nothing visible to the eye and 'routing' the board with a sharp screw driver did not cure the problem.

I now always check with a multimeter after assembly.
If you have a replicated cct you'll soon see the 'odd man out' in the group.

Note that meter polarity may influence the reading unless the test probe voltage is less than 0.7v.

Cheers,

Graham
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Postby Viewmaster » Sat Feb 16, 2013 10:00 pm

The Niptrix is now finished (at last!!), and is hanging on the lounge wall. :shock: ( OK, OK, dear, not permanently :) )
Here's a variety of stills from it.

Because I can now switch between two manual controlled oscillators for vert and hor scans as well as the fixed sync from the CD, the picture can be contracted or expanded for demonstration purposes..........
......One of the cat pictures is shown contracted using this manual sync.
for example.

These piccys were taken in daylight. The left hand vertical row of 48 pixels slightly reflects light from the window in the room in some shots !

I would like to thank all those on this forum who have made all those very helpful suggestions etc during my 5 month ordeal in building the Niptrix. :)

edit....I shall add a moving video soon on my web site.
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Postby aussie_bloke » Sun Feb 17, 2013 2:42 am

Big congratulations on your success with the Niptrix, I haven't been commenting on your progress but have been following it through, you've done a fantastic job those pictures look totally awesome!!! :D I look forward to seeing videos of it in operation! :D
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Postby Panrock » Sun Feb 17, 2013 7:24 am

Congratulations Albert. A fitting conclusion to some very hard work. This is something you can use in your living room too and will be a good way to demonstrate NBTV to those who haven't seen it before. I too have just just finished my project. Don't know about you but as for me, I now feel a great sense of release (and relief)! :D

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Postby Harry Dalek » Sun Feb 17, 2013 8:27 am

Great work Albert you are a master of NBTV ! All that is beyond me .
You made the smallest NBTV perhaps this is the largest LED NBTV display ?
And the first true Black and white one looks Amazing .
The electromagnetic spectrum has no theoretical limit at either end. If all the mass/energy in the Universe is considered a 'limit', then that would be the only real theoretical limit to the maximum frequency attainable.
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Postby Steve Anderson » Sun Feb 17, 2013 1:08 pm

May I also add my congratulations, a true example of plodding on with the job until done. I couldn't see myself even contemplating wiring up 1500+ LEDs...then the rest of the gubbins which were not insignificant in themselves.

Well done...the problem now is how you do a follow-up to an act like this?

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Postby Viewmaster » Sun Feb 17, 2013 7:02 pm

Steve Anderson wrote:Well done...the problem now is how you do a follow-up to an act like this?
Steve A.


Well thank you guys for your kind words.
Many others here are doing wonders that I wouldn't dream of tackling........Harry and his CNC, Aussie with his camera and
Iconoscope, etc.
Amazing projects guys.

Steve, follow up act at present is to try and get some decent video of it.
So far I have had those black running lines or part break up when videoing it. I have filmed it in daylight. I will try filming it in a dark room to try to get a better result.
Running a slow shutter speed helps but this cheats as it doesn't show the nice flicker. :lol:

O, then not forgetting that other ominous follow up act, Steve, that never seems to end, the Edikow machine. :lol:
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Postby AncientBrit » Mon Feb 18, 2013 6:43 pm

Congratulations Albert,

A wonderful result.
Are you going to write it up for the Newsletter?

Well done,

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Postby Viewmaster » Mon Feb 18, 2013 7:25 pm

AncientBrit wrote:Are you going to write it up for the Newsletter?
Graham


Yep. :)
But I really need to get some good video of it first so I can give a link to it in the article.
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Postby AncientBrit » Tue Feb 19, 2013 12:12 am

Good man,

I think it's important to document these achievements.

Cheers,

Graham
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Postby Viewmaster » Tue Feb 19, 2013 12:57 am

The problem at present is illustrated on this short video clip of yours truly on the Niptrix.
This was shot at 12 FPS setting on my mini DV camera. But it isn't a true rendition as the NBTV flicker is missing.
Shooting at faster shutter speeds gives the flicker but shows the running black areas which spoil the picture.

Oh well, anyway, you can see that I'm still alive! :shock: :lol:
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12 FPS.wmv
Shot at 12 FPS.
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