Creating larger light bars/letters/symbols with Leds/Bulbs - Page 1
Forum section: electronics / projects

author: MK14
author_rank: Super Contributor
timestamp: June 04, 2020, 02:13:38 am
content: Creating larger light bars/letters/symbols with Leds/BulbsFrom a hobbyist point of view. How do you make Leds (and sometimes bulbs if very retro), light up entire bars/symbols/letters/digits etc. Approx 3 inches by 3 inches, per char/digit/symbol/sign/shape/arrow/square.I 'almost' know how to do it. You sort of use light guiding plastic/glass/transparent-materials, tubes or half-tubes, possibly hollow.The effect I'm talking about is the method that most led seven segment displays use to cause the (approximately), 3 tiny individual leds, per segment. To light up in a bar effect, where the individual leds are blurred/merged together.I want to know, so that I can potentially make things (which can be read/seen at, e.g. 2 metres away) such as, very large seven segment displays, made out of 5 or 10mm, standard Leds.Hence things like 'EXIT' signs (only for fun, not for serious use), old arcade like machines, massive Led (7 segment) clocks, large traffic light (or similar) things. Etc etc.I know you can do a similar thing, by using many Leds, close together in a dot pattern and/or make/use 5x7 Led matrix character arrays, with a suitable number of characters. To do a similar thing.BUT I don't want (or like the look of), the 'dotty'/pixelated way that looks. I find it, partly unpleasant.I want the nice smooth look of a diffused light filter filtered.My google searches, unfortunately failed me. I just kept on finding lots of Led lighting things, rather than what I wanted.Also, I want to know what to buy and/or how to make these things.This is an example of what I want. Each of the 4 characters, could be turned on and off, by its own Led. Having multiple Leds, per character, is fine. As long as it looks smooth, like this:This is an example of what I DON'T WANT, because it looks all pixelated, and dotty:

author: themadhippy
author_rank: Super Contributor
timestamp: June 04, 2020, 02:21:01 am
content: one way is to use a diffusion filter,no need for anything fancy like rosco119 ,tracing paper and tissue paper both work.

author: MK14
author_rank: Super Contributor
timestamp: June 04, 2020, 08:31:54 am
content: Quote from: themadhippy on June 04, 2020, 02:21:01 amThanks.That sounds good, easy, quick and cheap.Leds are (relatively) very cheap now, so having lots is not a problem. The large square ones (approx 1 cm square), on a PCB, with the appropriate symbol (made by a pattern of Leds, e.g. 20 of them) on it. Then the tracing paper (or similar), should be good.

author: Ian.M
author_rank: Super Contributor
timestamp: June 04, 2020, 10:24:12 am
content: I would suggest two diffusers, physically separated, preferably by a similar distance to the spacing of the light sources, with light-tight barriers between segments. The rear diffuser evens out the illumination patterns of the light sources over the segment, and the front diffuser acts as rear-illuminated screen. Its possible to use a single thick diffuser (e.g. poured resin lightly loaded with colloidal silica) but some experimentation will be required to get the required effect.

author: MK14
author_rank: Super Contributor
timestamp: June 04, 2020, 01:06:43 pm
content: That makes sense. I intend to play with that idea (I can try 1, and then 2 diffusing layers, possibly using cut up plastic sheet, around 3 mm thick, with tracing paper on both sides), and see how it looks.So, it is as simple as the frosting inside the glass of the old tungsten filament bulbs, or modern white semi-transparent plastic Led mains bulbs. Somehow, I got it into my head, that it needed some kind of light conducting tube, shaped to make the symbols or effects you needed.

author: MK14
author_rank: Super Contributor
timestamp: June 04, 2020, 03:11:37 pm
content: Thanks for the help, I'm hopefully sorted now. But for anyone still curious...Amazingly, I've been able to find almost the exact projects, I was trying to do, online. So I can show you both the 'problem' and the real result I'm trying to achieve. Before I even do it.When you see it, you may understand why I thought there were light conducting tubes or something, because the first/old example seems to neat.Modern example, but with the pixelated/dotty effect:https://sudonull.com/post/8469But your tracing paper, one or two layer diffusers, will hopefully make it look better.The amazingly neat, old way of doing it. I saw/used something similar, a VERY long time ago. So wanted to recreate it, ideally using modern leds and stuff.https://www.popularmechanics.com/technology/gadgets/a23660/bertie-the-brain/Summary:Effect I wanted to achieve, it looks so neat (the really smooth looking 'O's):The effect I would expect, from modern leds:

author: themadhippy
author_rank: Super Contributor
timestamp: June 04, 2020, 03:38:32 pm
content: If you want to try the proper diffusion filter most of the manufacturers produce free swatch books of there range of filters,for examplehttps://www.10outof10.co.uk/acatalog/Colour-Swatch-Books.html#a26720

author: MK14
author_rank: Super Contributor
timestamp: June 04, 2020, 03:58:56 pm
content: Quote from: themadhippy on June 04, 2020, 03:38:32 pmThanks for showing me that. That is a useful option, if the tracing paper(s) method, isn't good enough.Decent filters are useful anyway, to make led 7 segment displays look neater.There are other project(s) I have in mind, which need similar capabilities. So, it is going to be nice, to find out how to do this well. Rather good results, will probably be good enough. It probably doesn't need to be nearly as neat as the black and white (old) picture, earlier in the thread.