Slashdot Mirror

The real issue is that all light bulbs really do need to have the rating of lumens. Wattage is power use, lumens is light output (obviously). Saying "40-watt equivalent" is empty marketing speak, no wonder they were disappointing. And then there's the whole light temperature issue, which is very difficult for a consumer to determine.

For my LED experience, I went with these LED bulbs for my chandelier (I was looking for a "25-watt equivalent") and have been very pleased. It may help that it's a cluster of bulbs in my fixture. Considering the lifespan of LED bulbs, I'm willing to pay a lot more per bulb providing the light output falls in the appropriate range.

I think you want to know the lux output not the lumens.

I hate to quote wikipedia but:
http://en.wikipedia.org/wiki/Lumen_(unit)#Differences_between_lumens_and_lux

Differences between lumens and lux

The difference between the units lumen and lux is that the lux takes into account the area over which the luminous flux is spread. A flux of 1000 lumens, concentrated into an area of one square metre, lights up that square metre with an illuminance of 1000 lux. The same 1000 lumens, spread out over ten square metres, produces a dimmer illuminance of only 100 lux.

Achieving an illuminance of 500 lux might be possible in a home kitchen with a single fluorescent light fixture with an output of 12000 lumens. To light a factory floor with dozens of times the area of the kitchen would require dozens of such fixtures. Thus, lighting a larger area to the same level of lux requires a greater number of lumens.

another source for the discussion of the difference between lux and lumen:
http://www.theledlight.com/lumens.html

C. Crane's GEOBulb looks very promising in terms of the future of LEDs, but the price is quite painful. I'm personally using some 120-130 lumen candelabra LED bulbs, which delivers close to the light of a 25 watt incandescent.

The LED bulbs are now coming in different color temperatures, so things are progressing.

as far as giant ones, my understanding is that they can't scale like that, but as far as replacement bulbs go for normal light fixtures, google brings up this, http://www.theledlight.com/ i'm sure there are LOTS of others too.

I go to http://www.theledlight.com/ and order A-19 style bulbs. The A/C hardly ticks on anymore because the rooms are cooler, and I'm saving 20% on my monthly electric bill.

LED lighting is already cost effective in certain situations. I priced a cable-hung low-voltage lighting system using LED-based MR-16 socket bulbs vs. 12 volt halogen incandescent and the system pays back in less than a year in electricity savings. That doesn't even count the significantly smaller number of bulb changes that are required.

If you have a large number of low wattage/low voltage light sources, CFL is not viable, but LED is. The power requirements are so much lower that smaller transformers can be spec'd, you can string piles more of them on a circuit, saving even more money.

There are some neat bulbs available at http://www.theledlight.com.

Car LED fixtures have huge margins. In fact, for the turn signals and brake lights, they should be dirt cheap since they're monochromatic.

You can get white LED lights for incandescent fixtures right now for about $20. CFLs are still probably more economical, but LEDs are catching up.

LEDs are over ten times more efficient and the directionality of the light can be solved in a number of ways.

What are you smoking?

Incandescent from my closet: 100 watts, 1690 Lumens or 16.9 lumens/watt.

CFL: 27 watts, 1750 lumens or 64.8 lumens/watt.

Let's find a few LED lights...

LED spotlight: 8 watts, 120 lumens, 15 lumens/watt.

Bulb toward end of page: 10 watts, 200 lumens, 20 lumens/watt.

How about this $70 bulb? Surely that one must be bright! Nope: 10 watts, 340 lumens, 34 lumens/watt. Better, though -- half as efficient as the CFL, but still too dim for good room lighting.

LEDs are pretty cool for certain uses, but they SUCK for general purpose lighting.

Well, that would be funny, given that most flourescent tubes have better color fidelity and, at least for white light, any LED lamps you can buy for a reasonable amount of money are going to be about as efficent as an incandescent.

I suppose this depends one what the person calls "a reasonable price Places like TheLEDLight.com has LEDs for $20 that use 10% of the power of incandscent lights and last for 10 years. And like CFL prices, I bought my first one for about $20, price for LEDs will come down. That $20 I spent can now buy about 10 CFLs, a few months ago I paid less than $4 for a pack with two bulbs. Having said that, the problem with LED lights is that they are not good for general area lighting, currently they are only good for point or spot lighting.

I keep waiting for the cost of 120 Volt LED "bulbs" to come down. Low power draw and lie expectancies of 30K hours or better! http://www.theledlight.com/120-VAC-LEDbulbs.html

I've been meaning to put up pictures and walk throughs on my site however since my wife just recently (last week) had a baby I'm a bit swamped. For suppliers try these two http://luxeon.com/ and http://theledlight.com/ . The first has the bulbs cheeper but the second link is a great source for drivers and dimmers. I recommend the "star" models. They come mounted to a little circuit board that makes mounting/retrofitting a snap and double as a heatsink. Sadly, most of mine are just DC driven with inline resisters at the moment.

Here's two more great sources:

http://luxeon.com/

http://theledlight.com/

I recommend getting the LEDs from the first source (cheaper) and things like powersupplies and dimmers from the second (better selection). The units with the star base attached are extremely easy to retro fit into existing fixtures also.

Since you claim to be a "lighting and electrical systems design student", perhaps you can help me.

I'm currently trying to figure out how to light parts of my apartment using LEDs. Judging by some color charts I found here, however, it seems exceedingly difficult to emulate daylight accurately. So far I'm looking at combining 5 color channels, but I'm not sure if it'll be adequate. Another problem is that they don't all work at the same intensity.

Do you have any suggestions or helpful links? Thanks.

It is always so dark under desks where you have to do all the wiring changes periodically, and no matter how many times I vow to put all wires high on a wall I always seem to end up under desks tracing wires. It would be pretty useful if I had one of these led flashlights on the end of 10m of ethernet that I could plug into a hub for whatever reason.

I'd recommend one of those ribbon ethernets on a selfwinding spool but the cheapo one I had broke pretty quickly.

I bought a EverLED Flashlight Bulb and installed it in a 4 D Cell Maglite. It's far better than any of the other LED flashlight solutions I've come across. Although it's not as bright as the Xenon bulb upgrade from Maglite, it uses far less power and it's brighter than the bulb that comes with the 4 D Cell Maglite.

These "screw-in" blubs you speak of are typically known as Edison bulbs. Reason should be fairly obvious.

That aside, LED Edison blubs have been out for quite a while. They are rediculously expesive, but I remember researching this as far back as when VOS Pad was posted on /.

Here are some quick links I found just by going to Google.

Link 1
Link 2
Link 3

I can find many. One i remember seeing a while back turned up in a google i just did:
http://www.theledlight.com/120-VAC-LEDbulbs.html
But they seem quite expensive. Another couple:
http://host205.ipowerweb.com/~goldenga/product_inf o.php?products_id=32
https://secure530.sectorlink.com/led-bulbs/eShop/1 0Browse.asp?Category=Mains
I dont think there is much demand for them at the moment though, and i doubt the ones with ~14 standard leds are very bright. Luxeon Star LEDs would seem like a better choice, but would get expensive quick, and I havent come across anyone who has tried putting them in standard bulb fittings.

This is an interesting idea. Are you thinking 5mm LED packages with this? Looking at some of the stuff available at The LED Light.com, there are some interesting options on this. The quad-colored LEDs looks particularly cool.

It looks like I could outfit my computer room with LEDs for about $200 for just the diodes. Figure another $100 in hardware and the time to scavange power supply parts, wiring and assorted other fiddly stuff from the office, and this could pay for itself within a year, easily; my lighting currently consists of halogen torchiere-style lighting to keep reflections to a minimum.

We're looking at a house at the moment, so this is going to factor into my decision. Ideally, I'd like to get one where overhead lighting is pretty much nonexistant so I can in an place LEDs in every room. I imagine some sort of controller based on a BASIC stamp where I can send X10 signals or some sort of encoded data over the serial interface to change pulse width and duty cycle to affect the overall brightness (or color, with those quad-packages). Interface this with a home automation controller PC and you could have some double-plus fun!

I can't wait to get started.

> Seriously, I used to love the old glow of a tube amp, lights in the room off, that nice orange glow coming from the back of the amp.....

You can have that back if you retrofit some of these babies into your transistor amp.

8-P

the reason they arent prevelant yet is because of price. over the next few years it should come down alot though. the best way to get started with led lights would to buy drop in replacement bulbs (edison type sockets). check out this site

I agree. Even in the pictures the rooms look too dark to live in. pricing is also a problem... you can go here and buy a 30watt equal for... $180.50! Has 36 LEDs.

I think LEDs will more than likely gain share in accent lighting to provide the "cool" effects like those in the pictures because there great for that and direct lighting (under cabnets?)

I also suggest that you look at using only compact flouresent lamps for lighting.

Skip that, go straight for the replacement: White LEDs. A little more upfront cost, but lower power yet, and a longer life.

The ledtronics link is especially good.

Any links to places that sell these LED's?

I've been googling, but haven't found anything yet (other than case-mod LED's).

One place to start: The LED Light.com. Fair warning: swallow that mouthful of {beverage} before reading the prices for the 120/240 volt "bulbs", unless you want to review input.

It will be interesting to see how long it takes 'em to start building units using Luxeons.

Also, do you just take these LED's and stick em in your light socket? Is it that easy?

Er, no, unless you count that brief glow as it becomes a friode. Normally you want to supply just enough power to do the job, which means you have to modify that 120/240V feed down to something the diodes can handle without smoking.

I have a CMG infinity with red led. It's a small, sturdy metal light that takes one AA battery and gives 40 hours of full brightness light, then another 30 or so of slowly dimming light. I use mine for general use and astronomy, and love it. It can take a beating, runs all year of heavy use on like a 4 pack of AA batteries. There's now an ultra version out with twice the brightness and half the battery life. See it here: http://www.theledlight.com/infinity.html Review here: http://ledmuseum.home.att.net/inf1.htm

To go along with the UV ink, a UV flashlight. Also, some good earplugs. Those are $10 and good enough that you can really enjoy loud music without going deaf -- they are not like the crappy foam ones.

Frankly, I suspect we'd do more for the developing world by adopting this sort of thing for ourselves

A quick Google search turns up The LED Light, and they have a collection of "bulbs" that fit into 120 Volt AC sockets (That would be them things in yer house, at least in the US)

Very expensive though - "36 LED bulb...comparable to a 30 watt incandescent bulb" costs $190.

Another site I've run into in the past is LEDTronics which looks more in line with the geek need for way too much information, and component-level purchasing. I can just see the mod case now...

Frankly, I suspect we'd do more for the developing world by adopting this sort of thing for ourselves

A quick Google search turns up The LED Light, and they have a collection of "bulbs" that fit into 120 Volt AC sockets (That would be them things in yer house, at least in the US)

Very expensive though - "36 LED bulb...comparable to a 30 watt incandescent bulb" costs $190.

Another site I've run into in the past is LEDTronics which looks more in line with the geek need for way too much information, and component-level purchasing. I can just see the mod case now...

Go buy some now: theLEDLight.com

My biggest problem with these bulbs is finding ones that have a nice, soft light. I don't want my bed room looking like an office. I spend enough time there as it is. Does anyone have experience with how 'pretty' the light from these is?

Here is a link to some products with white LEDs. Hopefully they can find some better uses =p

Here now, 600% more efficient than normal bulbs and also getting very cheap. They also switch on more gradually, making them less painful on the eyes.

If this works, then the new incandescents will be 1200% more efficient than normal incandescents. But the article says 60%, you say? It also says that current tungsten filament bulbs work at about 5% efficiency. Thus, .6/.05=12, or 1200%. (Implying, of course, that the efficient flourescent bulbs you refer to are 30% efficient.) I'd like to note, though, that white LED bulbs are also very efficient, and the 144 LED Medium Base Floodlight Bulb listed here, for example, is (assuming 5% efficiency for its incandescent cousing) 62.5% efficient, or twice as good as its flourescent cousin. It takes only 12 Watts to generate the same as a 150 watt tungsten incandescent.

I got mine from theLedLight.com; they've got them on special. You can also get them from Glow-Bug.

I got mine from theLedLight.com; they've got them on special. You can also get them from Glow-Bug.

• Cannot focus the beam, as the reflector is inside the LED itself
• Thus... the beam must be either non-focused, or too focused. Short focus LED lights have a very small range of 30 feet or so, while exceptions (like the PAL light) have such a focused beam that it is useless in close range)
• The "white" light, while impressive and cool, is not that great for night-time viewing. It can ruin your night vision, and does not display contrast as well as the yellow light. (of course, no one wants to put a yellow LED in their flashlight, even if they exist, because it's not "cool")
• pricey. (new technology is always pricey)

are available from www.theledlight.com. They make single and multi LED bulb replacements that fit into standard flashlight bulb sockets. Get 10X the battery life, plus ridiculously long bulb life (100,000 hrs). They will even fit maglites. I have no idea why companies are still making flashlights with traditional bulbs-- there doesn't seem to be any downside at all! (These bulbs cost $20 more than other bulbs, but if you've ever used a maglite regularly, you know how often the bulbs burn out-- why else would they have a spare in the handle? You'll get your money's worth by saving on batteries and replacement bulbs.)

The LED Light has a flashlight with 4 led and it runs 700 hrs on a set of Li batteries. 30 days on standard batteries. not bad.