[billman]

I am building a silk flame fire and noticed that most commercial ones are using 2 20watts 12v bulbs

Internals of a american dj machine:
American DJ Parts - Audio and Lighting Online Parts Store

I want to use Leds but would like to keep the brightness the same. What brightness Leds would I need?

 

[Scruffywolf]

Hey Billman. I'm not sure if LED's come in a certain "brightness" or say...lumens like an LCD projector but there are different types of LED's for sure. I think it all comes down to the lens configuration and how many LED's you use in your project. Some LED's are diffused, that is, the lens (the actual clear or coloured plastic body of the LED itself) has a less than smooth surface which breaks up the light that the LED emits causing it to scatter. Other LED's have a clear lens where you can see the LED's inner workings. Point one of these at your eyes and it almost blinds you. I used a pair of Jumbo LED's in my Bucky and FCG and they are very bright when viewed head on. If you want similar brightness to that of a regular incandescent bulb or even halogen, then you may have to combine several clear LED's in an array.....not really hard to do plus the benefits are, cheap to run and no heat! Check out some of the suppliers on line for LED home lighting and you may find a manufactured bulb that will fit exactly what you are looking for. You would be surprised what's out there now. Best of luck......'Scruff.

 

[monty1269]

Billman-
RUN down to your local "dollar Store" and grab a couple of those little skull/tombstones that flash... They are white plastic...about 6" tall. Grab a few (they're only $1)... then get home unscrew the back and they will fall aprt in three pieces. front half of the skull and back half .. PLUs the little LED package at the bottem THAT is the gold you are after! They are red and yellow/orange... The circuit board and battery are all one piece. VERY easy!! Drop that at the bottom of your little flame bowl you have, and you will be set!!

I've done the same thing...except I'm using them as cannon fire between two LeMax Pirate Ships....

 

[billman]

Good info. guys...

Hey, I knew I had some info. on this somewhere but I have like a gazillion things bookmarked (in no sort of order..ugh!). but here it is:

LED light output brightness levels are measured in "mcd", or millicandelas.
(from: LED_calculators )

I looked up the mcd on a hand cranked Durapro flashlight. It was rated at 15k mcd.

It would be nice to know the brightness of leds (by something I can relate to..um like my eyes or watts on incandescents cause I have experienced all the watt levels of bulbs in my life.)

This way I don't order to high or low output ones.

 

[billman]

Hey Billman. I'm not sure if LED's come in a certain "brightness" or say...lumens like an LCD projector but there are different types of LED's for sure. I think it all comes down to the lens configuration and how many LED's you use in your project. Some LED's are diffused, that is, the lens (the actual clear or coloured plastic body of the LED itself) has a less than smooth surface which breaks up the light that the LED emits causing it to scatter. Other LED's have a clear lens where you can see the LED's inner workings. Point one of these at your eyes and it almost blinds you. I used a pair of Jumbo LED's in my Bucky and FCG and they are very bright when viewed head on. If you want similar brightness to that of a regular incandescent bulb or even halogen, then you may have to combine several clear LED's in an array.....not really hard to do plus the benefits are, cheap to run and no heat! Check out some of the suppliers on line for LED home lighting and you may find a manufactured bulb that will fit exactly what you are looking for. You would be surprised what's out there now. Best of luck......'Scruff.

Scruff, you're right about led lens as well..
"Keep this in mind when buying LEDs for illuminating purposes - a 2000 mcd 30° LED puts out just as much light as am 8000 mcd LED with a 15° viewing angle. (The angle is half in both width and height, so the beam is four times as bright.) This is one of the reasons that ultra-bright LEDs are often "water clear", to keep the light going in one direction and not diffuse it all over the place."

from: Notes on LEDs

Also, "By way of comparison, a typical 100 watt incandescent bulb puts out around 1700 lumen - if that light is radiated equally in all directions, it will have a brightness of around 135,000 mcd. Focused into a 20° beam, it will have a brightness of around 18,000,000 mcd."

ugh...Bit confusing and more ugh...math... but I see they have some calculators at the site too. So, I think I'm somewhat good to go to figure out watts and mcd. Hope this helps others too.

But If someone has a simplier way to convert watts to mcd (generally) please let me know...or better yet a photo or video showing the brightness of various mcd leds would be great... Thanks..

 

[Scruffywolf]

LOL, great work 'Bro' thanks for all that info.....see? you CAN teach an old Dog new tricks, i suddenly feel ......dumb... I have really just gotten into the LED aspect of things this year with more to come but as you know, when you delve into something, you get an education along the way. Thanks again Billman for the info. It was all very.........enlightening 'Scruff