Illuminated house sign

[Bob Minchin]

I have the germ of an idea for a house sign (our place has a name not a number).

I reckon if I get some perspex sheet and polish the edges, any light that gets inside the sheet, should bounce around inside of the polished surface. If I then roughen the surface on one face side, the light should 'escape' and give an illuminated surface on which I can put opaque letters to be visible day and night. The question is how to get the light into the perspex. I'm thinking of a series of drilled holes into the top edge with white LEDs stuck in. The drilled holes will have a rougher finish and so the light should enter reasonably efficiently.

Does this sound viable??

Bob

[fictitiousemail]

Sounds poncy never mind viable

[Harry Bloomfield]

Bob Minchin wrote on 22/12/2008 :

Lidl had such an item and solar powered on sale mid summer. 3x3 solar panel on top, with a couple of white LED's back lighting a perspex panel, with numbers/lettering, all powered by a NiMh single cell. Even with the short days, long nights they run until around midnight.

[OG]

I've seem similar where, rather than roughening the surface, they use wax crayons that draw the light out of the surface and project it.

[Owain]

You can purchase these ready made as illuminated fire exit signs. This one uses an 8W T5 lamp

one uses LEDs give you a few ideas.

Owain

[meow2222]

yes, with a couple of tweaks.

Normally LEDs are pointed at one (or 2) edge(s) of the perspex to get the light in.

Secondly, if the perspex is evenly sanded, the light escape will be very uneven. Solution is to grade the amount of sanding across the sheet. Then you need to evenly distribute the light that does escape, a sheet of white paper would be a simple way, preferably acid free paper so it wont yellow.

Finally painting the far edge white will improve light level and evenness of illumination. Do the sanding with the LEDs lit so you can see where to sand a bit more to get reasonably even output. And dont overdo it. Oh - adding a reflective filme behind the perspex will boost light output and evenness further.

NT

[averagechapinthestreet]

If you want to outdo the neighbours, get one of these:

it in a perspex box (with hidden cabling), and wall-mount it!

[Appelation Controlee]

-------------------8><

Interesting concept - does it depend on a vacuum? ;-)

[Mike Harrison]

A good light source would be a CCFL tube - available cheap as a PC modding accessory.

It is hard to get the illumination even - the backlight assembly from a scrap laptop/TFT monitor would be a good start - there are all sorts of funky optical materials in there to get even illumination.

[Sla#s]

Lots of aircraft use an idea a bit like that. The only difference is they paint the panel black and just the writing shows through. It's done by using opaque white or clear Perspex, painting it white, then a top coat of matt black. They then groove the lettering in about 20% of the depth of the sheet. Painting an undercoat of white makes the illumination more even. It is illuminated by just putting lamps into holes drilled in the sheet every 6" to 9", mostly red ones. (they use a sort of backwards socket so you can't see the lamp) It looks really cool when done properly. I recon you would be better grooving the writing rather than roughening it. As for illumination the light source only has to be at the edge - you could put it in a frame - it doesn't have to be inset into the sheet.

Slatts

[Owain]

Nah, use one of these behind a translucent perspex(tm) sheet

[Calvin]

You might like to google the term "Total Internal Reflection" or "TIR". The technique is used quite a lot in industrial design, many cars use it for instrument illunination - as far as I can tell it's done because it is a relatively cheap way to make a good looking overall illumination.

[meow2222]

or go even wackier, use an old laptop with the screen behind thick toughened glass, then you can use music player type visualisations to present the house name in every conceivable funky but pointless way. And you can leave all the work to your teenage kid.

NT

[dennis]

Its a lot easier to use a cheap photoframe.

[meow2222]

can they run live video generated by visualisation software? I think you'd need at least win95 for that.

NT

[dennis]

8<

Mine will play video that has been pre-generated so its probably good enough.

[Harry]

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