NBTV without any moving parts. THE NIPTRIX

[M3DVQ]

I have found that drinking straws are exactly a tight push fit over 5mm dia LED's. I have ordered a pack of black party straws

Ooh! that's a good idea.
I've used heat shrink tube in the past but it's a bit fiddly and there's a bit of a knack to shrinking it onto the LED but not close up the hole at the end

[Steve Anderson]

Albert, a quick question which may be of use to others...where do you get such large sheets of Veroboard from?

When I was last in the UK I cleared out the last stocks that Cricklewood Electronics had. Small pieces, say up to 4" square are easy to get, even here...but anything larger is hard to find.

Steve A.

[Viewmaster]

Albert, a quick question which may be of use to others...where do you get such large sheets of Veroboard from?

Steve A.

Maplins......I bolted two large pieces side by side in a wooden frame to make the LARGE sheet...see photo. You can just see the join in the middle.

Notice BTW that all the alternate tracks have now been cut at every LED position.

[Steve Anderson]

Maplins....the largest they seem to do with the copper strips is their Stock No. JP51 and unfortunately it's still smaller than those I picked up from Cricklewood a year ago....seems like this stuff is going out of fashion...

Steve A.

[Panrock]

I have recently ordered 434-201 from RS for my line-of-light. This measures 455 x 110mm. That's nearly 18 inches long...

I am now steeling myself to install 201 LEDs onto it. Still, I thank my lucky stars/LEDs that this is only about one eighth of Viewmaster's burden! And no straws for me... I want the light to mix!

Steve O

[Steve Anderson]

I have recently ordered 434-201 from RS. This measures 455 x 110mm. That's nearly 18 inches long....Steve O

Oooh!! I'll have to check it out!!

This may be an idea, anyone you know does gemstones? I few few minutes in a tumbler should take the sheen off the LEDs themselves, but then again that's maybe not what you want...

Steve A.

[Viewmaster]

I have recently ordered 434-201 from RS for my line-of-light. This measures 455 x 110mm. That's nearly 18 inches long...

Even that would be too narrow for me. Hence my doubling up.
If one has plenty of dosh I seem to recall a Canadian lister on eBay who had very long AND very wide vero, but it was about 16 quid.

I am now steeling myself to install 201 LEDs onto it. Still, I thank my lucky stars/LEDs that this is only about one eighth of Viewmaster's burden!
Steve O

The white man's burden

201 to install....you don't have to steel yerself for such a tiny number Just lead and tin will do !!

[M3DVQ]

This may be an idea, anyone you know does gemstones? I few few minutes in a tumbler should take the sheen off the LEDs themselves, but then again that's maybe not what you want...

The other might be to assemble AND TEST the whole array, then bury the LEDs up to their tops in a black potting compound. Wait for the whole block to go hard, then take a belt sander to it

Course if an LED dies you're then utterly stuffed, so perhaps it's not the best idea

I have filed and sanded LEDs down in the past though. It can be a very successful (and cheap!) way to get obscure shaped diffused LEDs (wedges, etc).

Incidentally I was pondering a similar idea the other day when I saw line-of-light mentioned. If you embedded clear flat topped LEDs in a block of clear resin cast to the appropriate prism shape and polished up it ought to be be possible to achieve a pretty high percentage of internal reflection (if you threw enough enough hard maths at the design!).

Just idle musings really but might be an interesting concept for someone better at calculating optics to pursue

Finding the right resin to minimise refraction at the LED-Prism interface could be what causes that idea to come unstuck of course.

[Panrock]

Incidentally I was pondering a similar idea the other day when I saw line-of-light mentioned. If you embedded clear flat topped LEDs in a block of clear resin cast to the appropriate prism shape and polished up it ought to be be possible to achieve a pretty high percentage of internal reflection (if you threw enough enough hard maths at the design!).

Thank you! That's a very interesting idea - even though my maths is wanting....

Steve O

[gary]

Hmmm looking back I can't quite find the root reason for frosting the LEDs (if that is what is intended), however, for what it is worth, I found, to my cost, that trying to clean paint of an acrylic ball with acetone that it instantly turned the ball frosty. I haven't tried that with a LED but it may have the same effect.

[Viewmaster]

I think one should be cautious in embedding a great number of LEDs into a solid block.
Among the many things that has to be done in building the NIPTRIX is filing down the bottom flange on all the LEDs to fit onto vero.

So far I have done about 400 and I give them a quick 25ma flash test
as I do them. As I found one dud so I would never embed many into a block just in case.

[M3DVQ]

as I said, it is essential to complete soldering and test everything thoroughly before embedding it in goop

[Steve Anderson]

Encapsulating ('potting') an electronic assembly should be thought out carefully. In this case of Albert's NIPTRIX I don't see a problem, but if Steve O were to 'pot' his there would be a high chance of thermal breakdown. It's surprising how much heat is removed by radiation from the device and often even greater is convection. Air has a mass of about 1.225kg/m³ nothing compared to water at 1000kg/m³ but take that away and there's every chance that the Silicon inside will melt...it only requires about 200°C for that to happen.

Potting a device/assembly stops both radiation and convection instantly unless some form of heatsink protrudes from the potting compound. With these types of LEDs this is clearly impractical, a metallic grid screen arrangement provides optical screening, aids dissipation as it is metal and allows LEDs to be replaced. With so many at least one is going to fail due to 'infant mortality', the first 300 hours of operation being critical after which the assembly settles into the bottom of the 'bathtub curve'.

In the context of modern-day NBTV it is unlikely that any device is ever going to see 300 hours of operation unless one deliberately 'burns it in' well before a convention (say).

I would advise against potting as once done that's it, no going back....

Steve A.

[Viewmaster]

I have to cut 5mm dia black drinking straws to the correct length to mask the 1,532 LEDs from each other...see previous posts on using straws.

If anyone needs to cut quite a few they may like to consider clamping a stop bar to their scissors in order to make sure that every cut is of the same length.

Interestingly, I found that black 5mm party straws are of different sizes,
some fitting very tightly on the LED and others not so....

Depends on what party you go to I guess, as to how tight you get.

[Panrock]

Very nice Albert. It's thanks to your influence I have refrained from throwing away the drinking straw that came with a recent visit to McDonalds. It 'just might' come in useful some day.

<pedant_alert> You have got me wondering why you have 'only' 1532 LEDs to wire up when I thought it should be 32x48=1536. </pedant_alert>

Have you got a missing LED or sync pulse in there somewhere ... or have I got a screw loose?

Steve O

PS. As for my line-o-light, I've now settled down to doing 10 LEDs a day... it's all I can stomach.