# Need an omnidirectional LED



## KenTaylor (Dec 13, 2007)

It is getting time to upgrade my kerosene powered lighthouse to solar/LED. The current light source is a ca. 1950's Traffic Gard kerosene lantern which uses a Fresnel lens. The Fresnel lens is designed to use a (pseudo) point source of light. So, what I need is an LED with perhaps a frosted or faceted spherical lens. Is there any such thing? I am aware of the side emitting LEDs such as the EverLED. Perhaps one of them world work. 

I do not need a high powered LED as I don't want to use a huge storage battery and solar panel. Something on the order of a typical key chain light. The light is bright with only a kerosene flame. If I installed a 1W Luxeon the FAA would be after me as there is an airport only a few miles away.

TIA,

Ken 

p.s. Here is a picture of the lighthouse...

http://www.mediamax.com/boilermaker/Hosted/lighthouse.jpg


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## mds82 (Dec 13, 2007)

Sounds like you will need 4 led instead of one, point one in every direction. 

The other option is you can point one LED directly down onto a reflective cone so that the light gets reflected in all directions


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## Lightingguy321 (Dec 13, 2007)

could two side emitter Luxeon III or Luxeon I work? (flipped 180° from each other)


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## lctorana (Dec 13, 2007)

What's it for? Is it some sort of shipping marker?


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## Oznog (Dec 13, 2007)

Actually you might be surprised with how much power you need. A keychain light is great for making a bright beam a few degrees ahead. For this app the light needs to spread over hundreds of times the angle, although it can be much dimmer.

A 1W is hardly overpowered. Actually since you're talking solar, you want this thing to be efficient so you want to look hard at lumens per watt.

Hey, here's an idea- what if you want it to rotate like a lighthouse beacon, but don't want a mechanical rotator, you could use a bunch of LEDs in a ring and use a microcontroller or counter to turn them in in sequence. Probably want at least 2 on at once, turn off one on one side while turning on another on the other side.


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## SemiMan (Dec 14, 2007)

Lightingguy321 said:


> could two side emitter Luxeon III or Luxeon I work? (flipped 180° from each other)



I am with this suggestion. I would even try it with just one.

Semiman


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## KenTaylor (Dec 14, 2007)

Thanks for all the replies. The lighthouse is strictly decorative. I did the math again and 1 Watt is not too much - for 10 hours per day on time and a 12V battery that would be < 1 Amp-hour. Perhaps I will give one of the side emitting units (which have a cone shaped lens above the LED) a try. On the other hand the electronically rotating beam certainly is intriguing. 

Regards,

Ken


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## LEDninja (Dec 14, 2007)

The Tectite LPR-113 is also a side emitter PR bulb about 1/3 as bright as the Everled but it is a 6V only bulb. Probably will run from 4.5V to 6V.
http://led-replacement.com/lpr-113.html

If you want just a raw LED superbrightleds sells 360° Viewing Angle LEDs in white, blue, green, red.
http://superbrightleds.com/leds.htm


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## BIGIRON (Dec 14, 2007)

Great lighthouse.

I'm not nitpicky, but the rotating beacon might really get the attention of the FAA if you're that close to an airport. They ARE nitpicky.

You might wind up with a Cessna and a student driver in your yard.


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## Lightingguy321 (Dec 14, 2007)

What I was saying about 2 of the side emitters is that you flip them opposite each other and have them share 1 heatsink (one on top, the other on the bottom). Apart from that if you only need 1, find the best axis you want to mount the led on. What exactly is this going to be applied to.


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## SemiMan (Dec 14, 2007)

Just remembered Carclo has a side emitting optic as well that was designed to work with Luxeon stars. You may want to look at that too.

Semiman


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## mds82 (Dec 14, 2007)

Why not just shine 1 led at a Metalic cone, this way the light bounces 360 degrees?
just get a small piece of sheet metal and bend it to this shape


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## BIGIRON (Dec 14, 2007)

Aren't there a couple of led lanterns that already use the cone system? Maybe RiverRock?


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## bobski (Dec 15, 2007)

LEDninja said:


> If you want just a raw LED superbrightleds sells 360° Viewing Angle LEDs in white, blue, green, red.
> http://superbrightleds.com/leds.htm



I've used these when retrofitting my car's instrument lighting. The colored LEDs are just regular LEDs with a frosted coating.
The white LED is unique in that it seems to use a typical white LED's emitter chip, but puts the white phosphor on the outer surface of the LED rather than in the LED "dish" like most white LEDs.
Here's a line of 10 in parallel running at ~2 mA each... Ambient light was from a 27W compact fluorescent desk lamp about 2 feet above the desktop.




And at 60 mA (max spec'd continuous current):




And finally, along side a #194 12v automotive bulb:




Those are both running at full power, it's just a short exposure. As you can see, output is comparable.


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## Lightingguy321 (Dec 15, 2007)

I still think a small array of side emitter LEDs will work well too.


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## KenTaylor (Dec 16, 2007)

Wow! What a bunch of great ideas. The Fresnel lens is about 3" diameter by 3" high so a small cone machined from stainless and polished would do the trick. Actually I think the shape is supposed to be parabolic. I will have to do the math. (used to know how)

On the other hand, the Super Bright 360 degree LED sounds like a quick first try. For $2 it is hard to go wrong. I also need to retrofit/upgrade the instruments lights on my old MGB so perhaps I will order a bunch.

I was really joking about the FAA (I think). The lighthouse is only about 6 feet tall and the airport is several miles away. A church much nearer the airport has a rotating beacon on their lighthouse looking steeple and they have not yet been shut down.

Thanks again for all the input. I will fire up a new thread when I have something working. 

Regards,

Ken


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