The Blues for LEDs

Corey Burger writes "Seems somebody rolled out of bed on the wrong side today. The Globe and Mail's Ian Johnson delivers up a rant about the ubiquity of the new blue LEDs."

Cheap blue LEDs

[adamjaskie]

I recently bought a whole bunch of blue LEDs for $0.45 each from LSDiodes.com [lsdiodes.com]. This was a whole lot cheaper than ANY other place I could find. They shipped promptly, too. I got my diodes about 4 days later. They are on the west coast, I am in Michigan's Upper Peninsula, so thats pretty good. Equals the fastest shipping I have gotten from Amazon.com. Other places wanted like $2.75 for a blue LED. LSDiodes has 3mm, 5mm and two different sizes of surface mount: Tiny and miniscule.

Re:the LEDs are ok...

[jhtrih]

"Ricer" refers to the "moding" of "import" cars for looks and zero performance gain. I believe there are be far more derogatory words one could use to insult on of asian decent.

From the Urban Dictionary:
Usually some 17-21 year old male with heavily modified "externals", "posing" in some Honda (typically a civic), giving a bad name to those real tuners who drive fast Hondas!

Re:Why

[Scodiddly]

>2. Turn the device with the LED off.
>3. Drill the shit out of the LED*

4. Turn the device back on, and find out if the LED was actually part of an important circuit as well as being an indicator.

Alternate step 3: Use black electrical tape to cover the LED. Peel it back off when you're taking the eBay photos a couple years from now.

Re:Why

[ejaw5]

Even better:

1. Disassemble device
2. Locate offending LED
3. Apply heat (solder iron) and remove LED
4. If so desired, replace it with an LED of different color using the solder iron and resin.
5. Reassemble device

Paint

[nurb432]

Paint works well too...

Even a sharpie marker..

Choose a blue color and you can still have your light, at a reduced amount of luminosity..

Re:LED TVs?

[clearscreen]

one word : Jumbotron

Re:This line got me...

[eyeye]

There really are alarms like that, I had a brief stay at a nuclear plant that beeped constantly.

The theory is if an alarm fails it might not go off, but if it beeps constantly then you will notice if it fails.

Re:Then choose another device

[Idarubicin]

That said....unless someone gives him all his devices for free then geesh just buy different devices!

Ian Johnson writes a regular column for the Globe and Mail called The Chic Geek [globetechnology.com]. He also edits the technology section of the paper.

You can be certain that manufacturers regularly send him stuff in the hope that he will review it. Additionally, you can be sure that they will try to send him the 'sexiest' and most eye-catching products from their line--which is all the stuff with blue LEDs.

Re:Why

[Anonymous Coward]

4a. Replace corresponding series resistor.

Blue LEDs typically have a forward voltage greater than standard red/green/yellow ones. If you don't use a correctly-calculated series resistor, a lower voltage LED will receive more current and become a super-high-tech Black LED shortly after powerup.

No kidding

[Sycraft-fu]

I got an M-Audio Firewire 410 soundcard and the blue LED was beyond obnoxious. It was MUCH brighter than the red and green LEDs on the thing, by several times. Since it is the power LED, it was ALWAYS on. Also, if you powered the unit down, but left it connected to Firewire, it would proceed to blink at you, very frequently. I had put a peice of masking tape over it to dampen the light (and I could still see it through that). Finally, however, it just broke, and I'm not sending it in for service.

It's not the use of blue LEDs that bothers me, it's how damn bright most of them are. An indicator that my gear is turned on is nice. An indicator that my gear is turned on that I can see from outside at night (makes the room glow blue) is more than just a bit of overkill.

Go to Sam's Club

[Sycraft-fu]

They sell pants under their own brand called Member's Mark. They are nice, plain, dark blue jeans. They are also well made and like $13/pair.

Re:Why

[InfiniteWisdom]

4. If so desired, replace it with an LED of different color using the solder iron and resin.


And watch your new LED smoulder after a while. Blue LEDs trigger at 3.2 volts as compared to 0.7 volts for red and green LEDs. You also need to place a larger resistance in series with it, which is at best hardto do on a PCB that wasn't designed for it.

I vague recall seeing LEDs with curren-limiting resistances built in though somewhere, so make sure you use one of those.

Re:Why

[wtansill]

Go to Wal-Mart. They have tons of ordinary jeans and at decent prices, too. Or are you too damned good to shop at Wal-Mart?

Yes, actually, I am. I have better things to do than spend my hard-earned money at a store that deprives others of the right to earn a living wage, and kills off local small business in the process. Mall Wart is the Kudzu of the retailing world.

The color is fine. Brightness is the problem

[Animats]

On the annoyance front, there was a fad about a year ago for really bright power-on indicators. I have a Shuttle PC and a DVD player that will light up a dark room with their blue power-on LEDs. That's excessive.

The color, though, is correct. The standard NEMA rules for indicator colors, used on industrial gear for decades, are

• GREEN Normal status.
• AMBER Abnormal status. Operator should be aware that an amber lamp is lit.
• RED Trouble status. Operator should take action to make the red light go out.
• BLUE or WHITE On, or other non-specific meaning.

So blue and white are actually the default colors. Red should be used only for trouble indicators. We're still getting over the cheap red LED glut of the 1980s, when everything had red LEDs.

Anything that rackmounts should follow these rules. It's not only annoying, but a headache, to have red lights for non-trouble conditions in a rack of equipment. IBM always has.

Re:the LEDs are ok...

[schovanec]

Yes. I read an atricle about that in Consumer Reports once I think. The reason is that the light fall-off at the edge of the "light cone" is much sharper with the HID lights than with conventional lights. This causes them to appear to flicker from bumps in the road.

Shuji Nakamura is not sole inventor of LED

[lhpineapple]

"I've got a bone to pick with Shuji Nakamura."

I hate how people keep crediting Nakamura as the sole inventor of the blue LED. Yes, he did make the first working blue LED, but Dr. Theodore Moustakas here at Boston University developed the buffer-layer process for GaN months before Nakamura.

Here's an article. [bu.edu]

Dr. Moustakas is an awesome professor too. He loves to teach and does it well. He deserves so much more credit.

Re:Why

[sploxx]

Here is the math:

Wavelength: Minimum @ 400nm (violet). =: lambda1.
Maximum: 800nm (red) =: lambda2.
Energy E=h*f, with f=c/lambda => E=h*c/lambda, voltage difference per electron: U=h*c/(e* lambda).

=> pocket calculator => U_red approx 1.6V, U_blue approx 3.1V.

Resistor for blue LED @ 5V supply voltage, 20mA current: (5-3.1)volts/(20mA) approx 100 ohm.

Current through red led: (5-1.6)volts/(100ohm)=34mA.

34mA through the LED. Most of my LEDs would out of spec. here, but very often, it works! No warranty! :)

(Repost because of formatting errors)

Re:It's just because they're new

[gumbi west]

Actually, pure greens are fairly new...this [ucsb.edu] is the only reference I can find, but I recenly interacted with some people who work in a field where we were dieing for pure green LEDs for a long time, and they just recently got them.

Re:Go to Sam's Club

[Anonymous Coward]

Guess what, I used to work for Sam's and the jeans they brand as Members Mark are actually manufactured by Calvin Klein. This could be a good or bad thing depending if you like them too.

Yup, I tape a lot of LEDs "shut"

[ckedge]

My bed is only 8 inches off the ground so when I'm in bed at night my PC and all the stuff that go with it shine directly in my eyes. They're not blue LEDs, but they were still annoying as hell.

So I've used little bits of white electrical tape (match the case colors) to block them all out. Even the drive activity LED got covered over, at nights when it was going on-and-off it was exteremely annoying.

Now all I see are tiny dull green-yellow or orange spots, not a huge spotlight shining across the room. So I can still see the lights even during the daytime, but they are no longer the equivalent of little spotlights in the darkness.

Did the same thing to the LED on the speaker on the fridge in the kitchen, it was annoying at 2am when going for a glug of milk in the pitch black apartment to be blinded by the LED on it.

Here's a question - why do so few other people in the world use the BRAINS (you know, those huge amazing things that only we humans have) to SOLVE their problems instead of bitching about it all the time? Everyone always seems so supprised whenever I trot out some tiny little thing that I've done to solve a problem or make a job easy. It's not rocket science.

my blue LEDs

[Eil]

I have exactly two blue LEDs, and I had them easily 3 or 4 years ago when they were "expensive". It's a long story, but suffice to say I've been a fan of LEDs and their different colors and uses since childhood. I have a full-tower Antec case and I've never really been a fan of case-modding (I like beige just fine, thankyouverymuch), but I once happened to see some blue LEDs from the same online store that I bought my CPU fan from and bought a pair on a whim.

I soldered them in, replacing the green and amber power and HDD LEDs respectively, and turned it on. Looking, of course, directly into them. BIG MISTAKE. I felt like I was temporarily blinded for several minutes. The HDD one is not a big deal since it only flashes occasionally and never stays continuously lit for more than a second or two, but the power LED is on ALL THE TIME and if I turn off the lights it can illuminate an entire half of the room all by itself.

Fortunately, the LED bezel in the case directs most of the beam straight ahead, so it hasn't been that big a deal, though I've been tempted more than once to figure out the current and voltage and solder a resistor in series just to tone it down a bit.

LED replacement strategy.

[evilviper]

In reality, the color isn't too much of a problem. The problem is that they are so high powered.

While I will admit, the fact is that certain colors appear more piercing than others (due to how much they scatter), the power is the real issue. He mentions that he is bothered by RED LEDs, but in reality, Red is the most gentle color there is. Back when I was making my own home-made LED flashlights, I quickly discovered that red is an awful color to use, because it scatters so much that there's very little light left where you are pointing it. Blue worked well, but too well. It's soo powerful that you loose your night vision, and since LEDs weren't as bright as regular bulbs, you needed your night vision, otherwise the LED flashlights were useless.

Green/Amber are the best colors. No loss of night vision, but enough light to iluminate.

I have a solution to this problem though. What we need is an indicator that is not self-lit at all. Back before LEDs, most applications used a colored piece of plastic/metal to indicate status. What we need is something like that, but updated so they can be a drop-in replacement for LEDs.

I'm thinking maybe a tiny canister, with 3 tiny, colored, magnetized ball-bearings. A simple electro-magnet could move any of the 3 to the display window.

So, it would be just as simple as the multi-colored LEDs, extremely low power, and almost as small. As an added bonus, you won't see these status indicators when all the building lights are out, and you WILL be able to see them when it is bright out. If you've ever tried to see if your LED is on while it's in direct sunlight, you know what I'm talking about, and certainly see the advantage of this idea.

4RED and 1BLUE LED = hope for 3rd world

[dutchtommy]

Recent research in Japan has led to the developement of PINK LED lights (4 red to 1 blue) in growing plants. It seems that the low power, high yield (400% higher growth in some instances) are a savior for some countries of the future. LED use so little power, hook them up to solar/wind and you can grow huge amounts of food in low light, basements, attics, etc without the problems of:Heat, replacing bulbs, power supply, cooling of housing from bulb/halogens. This will lead to great developement for 3rd world countries, cold countries, and home 'weed growers' to grow with impunity. GOOD JOB NAKA!