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Old Feb 06, 2008, 06:46 AM
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Evansville, IND
Joined Oct 2005
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Well I am using LEDs on my tug and at first I had them hooked up to a 9v battery with no resistor and it worked fine nice and bright than I went to 4.8v with no resistor and they all work fine and I have 21 lights on my tug.
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Old Feb 06, 2008, 11:55 AM
Sea Dragon-Lover
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PDX, OR
Joined Dec 2002
10,227 Posts
Quote:
Originally Posted by elektrofuzzi
I feared as much,...
nothing to buy at a store...

Your negative is a two-part silicon rubbber mold?

Think, i should make a molding too. This will not be my last floodlights in 1/50 i will need, and the methode i worked it for the "Abeille" is too expensive to build 10 or 20 of it.

Peter
I can make extras if these suit your needs.
e-mail or send me a PM.

Aimee
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Old Feb 07, 2008, 05:05 AM
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Blackpool, Lancs
Joined Feb 2006
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Some LEDs do have resistors built-in. Some LEDs can be run off a small 9volt battery because the internal resistance of the battery limits the current. Most object to that kind of treatment by putting out their lifetime light output in a few milliseconds, and then dying. (Been there, seen the film, eaten the pie)
The only safe way to ensure long LED life is to apply your own current limiting, using the information from the calculator link mentioned earlier.
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Old Feb 08, 2008, 12:19 AM
Boats on the brain!!
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Arnold, Mo.
Joined Jul 2005
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Quote:
Originally Posted by elektrofuzzi

If you have seen it on my album, my floods are made of brass with 2 SMT LEDs in.
Do you solder your SMT LED's onto a pc board or do solder a wire directly to them?
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Old Feb 08, 2008, 12:57 AM
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They are directly soldererd at the bottom side of the LEDs. There is not enough free space for a PCB.
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Old Feb 20, 2008, 11:28 PM
Boats on the brain!!
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Arnold, Mo.
Joined Jul 2005
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Those SMT LED's are a lot bigger than I'm used to seeing and they look like they have a bezel. I'm used to seeing the ones that are the size of a pencil point. Where did you get the ones pictured?
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Old Feb 21, 2008, 02:04 AM
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Joined Feb 2008
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Hi
There is a little round cavity filled with resin to mount the 5 chips in. But this has no lens effect, emmitting angle is about 180.

Packaging is one of many SMT types you can get.
in the pict. from the left:
0603, 0805, 1206 (maybe the one u mentioned), PLCC, a siede-looking PLCC, and the upper- and downlookig side of the PLCC used in my floods. As a comparison a standard 3mm LED. Actually i'm experimenting with a 1W luxeon in the background.

Most of such special tools and parts, i get on ebay ;-)
They offer the best variety of goods...
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Old Feb 21, 2008, 11:17 AM
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PDX, OR
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Peter,

Can you post a "mini how to" showing how you solder and assemble those
SMT LED. I haven't used them, because it seemed like a hassle to solder any
wiring to those tiny contact points.

The Luxeon LED are nice, but heat build up is an issue.
I heavily heat sinked these four builds below, for the nephews and friends...
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Old Feb 21, 2008, 12:03 PM
What is this a center for ants
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United States, CA, Beverly Hills
Joined Jul 2007
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I just picked these up on EBAY for under 10.00 (bought a bunch) different configurations. 9v with a switch and cool little bezels.
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Old Feb 21, 2008, 02:36 PM
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Joined Feb 2008
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Hi Umi

to tell the truth:
It IS a hassle...

You need a very small tip at your soldering station and a slow hand.
Main problems are:
-to fix the parts
For building my neons, i used a double adhessive tape to position the four 0805 SMTs in a row with the resistor.

-find a tiny wire to connect
The soldering pads of SMTs are not as solid as eg. common resistors. If you use a rugged wire to sold on, pads can be ripped off the ceramic.
You may use a tiny cable like the left one. A industrial (called "wire-wrap") cable with diam. ~0.01 inch. and a teflon isolation.
My favorite is the right one. The green is an enamel farnish and the isolation too. To de-isolate, hold the tip of the wire into a drop of tin-solder and the farnish will melt down. Usualy it is used to correct industrial PCB layouts. I believe you can bump it with ~100mA, that will reach for my neons at 10 mA.
IMHO i got it from Conrad.de or Buerklin.com.

And the rest?
Soldering, even a little smaller...

The third pic:
The downsight of my halos without a PCB. As i remember there were 5 anodes and a common cathode on each SMT. As our LiPo-friends will say: This is a 2S 5P connection. On each chip 5 LEDs working parallel, and 2 chips in series.
Wiring is done by a simple connecting lead of the resistor. Pads of the PLCC are much more sturdy than the pads of a 0805.

Any questions?
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Old Feb 21, 2008, 09:21 PM
Boats on the brain!!
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Arnold, Mo.
Joined Jul 2005
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Thanks for the info, that's what I needed to know.
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Old Feb 28, 2008, 09:56 AM
Registered User
Joined Feb 2008
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Let me show my newest project to you...

With the help of UMI's floodligths (THX!) there was grown a little collection of double fired 1/50 floodlights with sunny white 3mm LEDs.

Due to the housing of the LED is to long the front lens has been trimmed on a little lathe, the end flange with a diam. of ~4 had to dissapear too.

I drilled the floods from the backside with a 3mm milling cutter, its zylindrical profile will fit the best to the now zylindrical LED. Attention not to break the "front glass pane"

Surfaces of the drilled housing and the trimmed LED shows a little opal and matt.
But that doesn't matter. Anyway u have to fix the LEDs, put a little dot of epoxy glue on the front of the LED and put it in. And you can see - nothing! Epoxy fills the microstructures of drilling and it looks like LED is molded in (Pic: low_glowing).
Second pic is at nominal current (20 mA at ~7V, 2 LEDs in series)
Third one is the collection at a "table top foto" lighted by itself ;-)

A little revision have been come up:
Orientation of the LEDs is actualy:
_____________
I...................I
I..+O-...+O-....I Idea was, to connect the LEDs in the center
I____________I and use the outer wires for mounting the flood

The better way will be:

_____________
I.....+..R..-.....I In this way you can placa a SMT resistor directly
I.....O.....O.....I on the flood and distance between the 2 free pins
I____I___+___I looks much more realilstic when used as a mount.

But...
too late for my series...

over again:
THX to umi

Peter
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Old Apr 06, 2008, 10:54 AM
Veni, Vidi, Feci
patmat2350's Avatar
Motor City
Joined Dec 2004
12,381 Posts
Follow up to a couple earlier posts here:

1. The side-emitting LEDs shown in post #1 are imported by someone called Everstar Merchandise Co. Ltd. I've been told they are "concave LEDs", for the inverted cone tip.
I've not found the LEDs loose anywhere... you may need to invest in a whole string to get a few, or several strings if you want colors.
Searching through listings on ebay and Amazon, I see a few offered, if you can't find them in a local store when the Christmas season rolls around (that would be Halloween around here!).

2. Not all Christmas LEDs are of this type. The faceted globe type has a plain old end-emitting LED inside.
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Old Apr 14, 2008, 07:13 PM
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PDX, OR
Joined Dec 2002
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Spent the weekend at the model railroad swap meet, showing
boats, and flying micro helicopters... and repairing the combat warship.

I got back and figured the SDM tug should get a bit of equal time...
Five Floods installed.. I was lazy and didn't color correct them...

All are 3mm white LED that I cast into the fixture.
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Last edited by Umi_Ryuzuki; Apr 14, 2008 at 09:16 PM.
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Old Oct 24, 2008, 06:16 PM
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Stuttgart
Joined Jan 2004
1,781 Posts
Thats pretty ingenious using clear resin. I guess its also easy enough to just replace the whole thing if the led should burn out. If I ever need some, I know who to beg!!
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