LED light angel?

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Hey
I'm building a table with LED in it...
But I don't know if I shall buy LED with an angle of 20 degrees or 140 degrees....

The distance from the LED's and the table's glass surface is about 2 cm...

Can any of you guys tell me if I will see any different at that short distance ?

//B4Me

uC's: Atmega16, 32, 64, 128 and Attiny13
Lang.: C
Interests: Small scale robots AND sensor monitoring system

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of course you will. Draw it out on a paper. you will get a much much bigger area of light with this 140 degree LED.

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Hmm I think soo.... but will I be able to see this ekstra light on a glass plate ?
Or will it just be a waste of money ?

cause the lights energi will still be most powerfull in the center (let's say 30 degrees...)
Or am I totally wrong here ?

Has any of you tried something similar ?

uC's: Atmega16, 32, 64, 128 and Attiny13
Lang.: C
Interests: Small scale robots AND sensor monitoring system

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Well could you specify, which LED's are we talking about ;)
Most of the information can be found in the datasheet. (As always)
And you are illuminating a piece of glass? like window glass or something different? It's just that Light tends to go through glass objects ;)

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You can be shure that the center is much more bright than the outer parts. The angle, basicly, dictates the distance between two adjacent LED's if you want uniform illumination, and usually bigger means better. Since it is 2cm, I would suggest you to use 120º LED's SMDm tipically PLCC2 or PLCC4.

But, since this is not too expensive, buy few of any kind, and test is yourself. This is, by far, the best way to see which fits better your spectatives. There are many other factors that would affect the result, specially the table surface, texture, material, etc. Been there, done that. Without the definitive materials and few samples of the components (better if you have more than 2 different angles), then you are probably lost. Remember that distance from LED to the target surface is also an important paramter.

I'm using white LED's and Orange LED's, all SMD PLCC2 and PLCC4, and the best results I had were with about 1-2 cm from LED to surface, and a translucent opal-white policarbonate surface.

Post your results, please.

Guillem.

Guillem.
"Common sense is the least common of the senses" Anonymous.

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Hehe, Guillem, how did you do this ? 120º
I use the workaround degr. and so, º is so much nicer :)

Nard

A GIF is worth a thousend words   They are called Rosa, Sylvia, Tricia, and Ulyana. You can find them https://www.linuxmint.com/

Dragon broken ? http://aplomb.nl/TechStuff/Dragon/Dragon.html for how-to-fix tips

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Thx for the reply's.

I've think'd about making the glass "Frosty" with some kind of glass film... as it's to expensive to sandblast a 60x120 cm plate :(

And I'm still afraid, that I just waste a lot of money if I'm going to buy the wide angle LED's....
I'm going to use 264 of them....

uC's: Atmega16, 32, 64, 128 and Attiny13
Lang.: C
Interests: Small scale robots AND sensor monitoring system

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The brighter the led the narrow the angle usually.

John Samperi

Ampertronics Pty. Ltd.

www.ampertronics.com.au

* Electronic Design * Custom Products * Contract Assembly

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Okay js
I think I'm just using standart white LED's with 20 degrees...

uC's: Atmega16, 32, 64, 128 and Attiny13
Lang.: C
Interests: Small scale robots AND sensor monitoring system

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You can use Piranha (what is called Superflux) LEDs. They output about 8000 mcd at 140 degrees and relatively cheap (~ US$ 0.35). I have used them for ascent lighting. Narrow beam LEDs might produce light spot on the surface. There are quite a few suppliers on the ebay selling this.

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@Plons: Alt-167 º
(167 on the numeric pad only - doesn't work with the top row keys)

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-eret .. th5s 5s the res43t 6n the n6teb662 ....

.... if I forget to turn numlock off afterwards. Thanks :)

Nard

A GIF is worth a thousend words   They are called Rosa, Sylvia, Tricia, and Ulyana. You can find them https://www.linuxmint.com/

Dragon broken ? http://aplomb.nl/TechStuff/Dragon/Dragon.html for how-to-fix tips

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you want to illuminate the whole glass plate? use Lumileds K2 5W LED. it illuminates 170 degrees and VERY brightly. They also have side emitting LED's that illuminate light only to the sides. Very neat "little" LED's

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bloody-orc
My plane is to make a big matrix (12x22 leds) over my coffee table...
like this one just digital...
http://www.becausewecan.org/LED_...

In a table like this
http://www.ikea.com/dk/da/catalo...
(I'm from denmark ;) )

I can see that EvilMadScientist are using normal 5mm LEDs... but they are also having almost 2 times as many LEDs..

uC's: Atmega16, 32, 64, 128 and Attiny13
Lang.: C
Interests: Small scale robots AND sensor monitoring system

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Well, you can buy a thin policarbonate Opal-white or Ice-white (the later more 'frosty like') and put it underneath your glass. That helps a lot to difuminate the led light and to distribute it evenly over the surface.

About 'wide angle' LED's, since they are normal SMD ones, they are not more expensive than classic 5mm ones. Piranha (superflux) are also more expensive. I know that automotive manufacurers right now only use SMD ones, and they always consider prices.

Anyway, I suggest you to buy few samples of white LED's with different angles, and then test them to check the result. You also have to play with distances between LED and surface.

Remember that usually most manufactures sell the same LED IC with different angles, thus they emit the same amount of light (total flux), but they are brighter for smaller angles (it is only question of geometry), since they concentrate more energy in an smaller area. But that only means that all the light is delivered onto an smaller surface, thus you need more LED's to illuminate a bigger area.

Guillem.

Guillem.
"Common sense is the least common of the senses" Anonymous.

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I would use brushed plexyglass under the table... (As all the casemodders do ;)). But I do think, wider is better. Just remember: looking straight into a superbright white LED can cause permanent eye damage!!!

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bloody-orc wrote:
I would use brushed plexyglass under the table... (As all the casemodders do ;)). But I do think, wider is better. Just remember: looking straight into a superbright white LED can cause permanent eye damage!!!

Is that true??? With lasers we have a class rating from class I to IV. Class I is eye-safe. So superbright LEDs have a higher class rating? Is it on the package somewhere? There are tons of regulations about this kind of thing.

Go electric!
Happy electric car owner / builder

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regulations regulations... who the hell reads them? I'm just talking about my personal experience. I have blinded myself for hours just from looking into a LED for a very short time. sec maximum. And that was just 14cd led. I don't dare to watch into a brighter one.

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I my memory form my old life, when I worked with lasers, is still in use, then most of the 'power LED's' are class 1M. Check out Osram datasheets, since they have a big label regarding this:

Note:According IEC 60825-1 (EN 60825-1):
LED RADIATION
DO NOT VIEW DIRECTLY WITH OPTICAL INSTRUMENTS
CLASS 1M LED PRODUCT

This is from Golden Dragon. Also in other LED's like LO E6SF. These later ones are really bright, even at 20mA, when they are rated at 50mA.

Guillem.

Guillem.
"Common sense is the least common of the senses" Anonymous.

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Try to find out if there are any home shop machinists in your area. That's a very large piece of glass to fit into a sandblasting cabinet, but you never can tell. Some people with home shops can have some pretty impressive equipment. They might offer you the service in exchange for something else (like help in building their own light-up table!)

It's worth a try.

Tom

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Hey benedict
As I mentions before I'm thinking about using these glass films to make it look "frosty"

uC's: Atmega16, 32, 64, 128 and Attiny13
Lang.: C
Interests: Small scale robots AND sensor monitoring system

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Quote:
I have blinded myself for hours just from looking into a LED
Were you at the same time under "medication"? :lol: or smoking something?

John Samperi

Ampertronics Pty. Ltd.

www.ampertronics.com.au

* Electronic Design * Custom Products * Contract Assembly

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bloody-orc wrote:
regulations regulations... who the hell reads them? I'm just talking about my personal experience. I have blinded myself for hours just from looking into a LED for a very short time. sec maximum. And that was just 14cd led. I don't dare to watch into a brighter one.

OH! ok...this is different. That is called "saturation". It's only temporary and doesn't reflect permanent damage. (I'm not suggesting everyone goes out and looks at bright LEDs now!)

As Guillem pointed out, if you look at it through let's say a magnifying glass, then you would actually burn your retina. But since the "beam" is so diffuse normally, it won't do that. Again, don't take my word for it.

Go electric!
Happy electric car owner / builder