Blue light was so rare, we didn't have glasses

This is really specifically wild for me to stumble onto here. Let me explain. In the early 90s, a few of us in the clubs were into the whole "cyberpunk" movement that was pretty new back then.

Some club denizens went as far as to create electronic apparel, with an LED or two, and one guy even made a skin temp sensor and connected it to an LED bar graph, so the more he exerted himself the higher his temp would show on his arm.

Anyway.... everyone has either red or green or yellow. I wanted a blue. Couldn't find one.

Internet was pretty limited back then, so a lot of shopping in parts stores, catalogs. Etc....

We finally found a supplier in China that manufactured blue LEDs, but we'd have to buy like 250,000. Somehow this dude gets a hold of exactly 5 of them. He worked a deal with a store who ordered the he quantity and let him buy 5.

Craziest thing, the turn on voltage for the ones We used was 6V. So, strapping 4 AAA batteries somewhere on you would give you 6V.

These blue LEDs from China needed 5V.

Took a while, but we figured out that rechargeable batteries output 1.25V, so we used 4 of those to achieve the 5V turn on voltage. The whole thing took about a year while we figured it out.

Haven't thought about it in 30 years. Then I run across this random article telling me exactly why what I tried to do 30 years ago was so difficult.

/endstorybro

The creators of the bright blue led won the Nobel prize in physics for it as it allowed us to create white light LEDs that are now the most energy efficient form of illumination for homes and saves countless billions of dollars in energy costs.

The inventors won the Nobel Prize.

Blue LEDs have replaced amber tone activity lights in most electronics, and the disturbance to sleep patterns is evident in everyone’s behaviors globally. I have to tape over nearly every LED on every piece of electronics to tone it down enough. Otherwise it illuminates an entire area if the lights are turned off.

Blue LEDs are the scourge to sleep.

I hate blue LED's. My eyes can't focus on them properly. If you show me a red LED ticker alongside a blue one, the red letters are pin sharp to me and the blue letters are blurred as if I'm not wearing glasses.

Just get a nice pillowy sleep mask. Absolute pitch black heaven.

If you wake up to go to the bathroom, sleep disturbed. Gotta turn off and black out those blue lights. Sleep masks are nice, but only helps while you have it on.

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I think I would of just used a resistor in parallel with the led

Interesting.. so what you’re saying is that people back then could fall asleep immediately, even right after using their iPhones?

I remember when red LEDs first became affordable and widespread, we used them on our boat to read charts in the dark without ruining night vision. But the gap between those first cheap red ones and LED screens or bright white ones for headlamps and flashlights seemed like it took forever.

I remember the late 90s, when electronics started being plastered in blue LEDs, for a "futuristic" look. Usually combined with silver coloured plastic.

They were extremely expensive when they first became available. The blue LED power indicator in a preamp added $200.00 to the cost (including markup) according to the design engineer.

Funny you should mention rechargeable batteries. A while back, 14 years or so ago, I was dabbling with electronics and wanted to swap my xbox360 controller and front panel led's from Green to something else, like purple. I ordered a bunch of purples, blues, reds, etc. I wire up the purples to the controller. Nothing. And these were so small, if the soldering iron stayed on it for more than 2 seconds it literally would disappear in a puff of smoke.

Apparently I'm telling this out of order but it helps. I did the red ring on the 360 front panel with the purples fine, so I know theyre good. I replace the purples with blues and it lights right up. I put purple back, no dice. I'm fiddling around and I forget how but I plug the charging wire into the controller direct and I get flashbanged by purple lights. Similar to your story I found out the rechargables had less voltage. So the red ring front panel is hardwired and getting full juice, but wireless, no dice. Pop in the usb charger and yeah it would light up. Also confirmed regular AA's would work, but I already had all these battery packs so I wanted to stay with the lower voltage.

So I opted for a blue/red/blue/red X pattern and left the purples for the front panel. Cool side effect was that as the batteries died the blue led's would get dimmer and dimmer until you just had 2 bright red led's and then the controller would just die. I think this may be a reason they favor red for emergency systems as it seems to require less power.

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Series but yeah

Nail polish is good too. You can use it to make them dimmer but still visible.

Red LEDs do require less power. The forward voltage on a red LED is about 1.8V at 20mA. The forward voltage on a blue LED is about 3.6V. That's 36mW of power for red vs 72mW of power for blue.

Blue light has more energy than red light (higher frequency/shorter wavelength).

I think they generally favor red over blue for emergency systems, though, because red light has less effect on low-light vision. So if the power goes out, your red-lit emergency signs don't blind you in the dark.

That too because lord knows what happens when the tape falls off my optical to rca adapter. Why this thing has a Batman spotlight built into it, I'll never know.

In 98 or 99, blue LED's we're still so expensive that I bought 1 to replace the green LED on my PC's power light. I was going to put them all over the PC case, but instead went with some cold cathode tubes.. the tubes and power supply was still cheaper than buying 1 LED. If I remember right, the LED's were like 25$ each..

I was at UCSB when Nakamura won. He was apparently pretty stoked he didn’t have to teach anymore.

Wonder what the science behind this is

Connect that stuff to a power strip with an on/off switch and turn the whole lot off when you go to bed. Apart from your phone charger it's not like you'll be using those other electronics when you're sleeping.

You might be a more extreme case, but human eyes can't focus on blue light as well, period. I know this first hand (and second, and third) from calibrating three tube RGB projectors back before LCD/DLP.

I also read about it being used in image compression. If you split an image into R, G, and B channels, you can save the B at half resolution and the difference is nearly imperceptible to human eyes, whereas it is easily seen if you do that with R or G.

First bright blue LED I ever saw was on the PS2. I got a week to play with it pre-release due to work. Before and after gaming sessions at night, that piercing blue light felt like the goddamned future.

The lens and cornea of the human eye absorbs shorter wavelengths (blue) better than longer wavelengths (red) so less blue lights reach the retina.

The cones the retina uses to see longer wavelengths are active over a wider array of wavelengths vs the blue cone.

So it is easier for your eye to sense longer wavelengths of light than the blue light.

Ah thank you, that make sense.

I remember a physics professor in highschool being very excited about the blue led telling us it would allow for white light LEDs.

However there's an issue with emergency signage. Red is the color of danger, stop, while green is safe, go. Exit signs in areas of low literacy are green and green are becoming more common in the US to be more inclusive of people who can't read.

It's frustrating that the headlights from heall are more blue tinted, so no only ate they brighter, but the person using them can't see as well, so they make them even brighter.

Hikaru

For the few of us that lack a separate office for our equipment, some of us need to live in one room, I use my computers to render video, and to render 3-D projects while I sleep, it’s crazy that I have to black out all the LEDs just to keep them quiet.

This is why the Dreamcast failed—orange light.

I understand that it's not always possible for everyone, but this is exactly why I have zero electronics in my bedroom (aside from my phone charging on my bedside table, but that doesn't have an always on LED).

That plus blackout curtains have really improved my sleep!

My idea of classy is still stuck on brushed alu and blue LEDs.

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Same. Among certain specific geek circles it was a huge deal at the time that the PS2 had a blue LED.

>I also read about it being used in image compression. If you split an image into R, G, and B channels, you can save the B at half resolution and the difference is nearly imperceptible to human eyes, whereas it is easily seen if you do that with R or G.

Never heard of chroma subsampling happening in RGB, generally that's converted to something like YUV which is a Y channel of luminance (about 58% derived from the green channel) and two UV chrominance channels. Both channels of chrominance are then subsampled horizontally by 50%, reducing 1/3 of your original data without even getting to the compression stage. Pretty much all compressed video you ever watch has the chrominance subsampled 50% vertically as well, meaning you've cut the original data size in half.

Point is, not just blue getting subsampled, and since that's what everyone is constantly watching it's pretty safe to say it turned out alright.

You are supposed to use a current limiting resistor. LEDS dont last long with excess current which you will get without one

Fucking quantum physics man.

I was 13 lol

Agreed, best to have forms of RF away from sleep spaces, current situation has a single room for both work and sleep, so black out curtness, sound absorbing wall blankets, and blacking out all BLUE LED's on things. Even the RED LEDs on power strips are too bright now. Have to tape over them as well.

Thankful to Lévoit Air purifiers for having the option to TURN OFF the LED panel. Also thankful to Govee humidifier for having a "LED panel brightness, and schedule on and off" settings.

More electronics need to think about the brightness in dark rooms. Light pollution is a ongoing battle.

There's a movie theater where I live that chose to make its menu all bright blue LEDs and it's almost literally impossible to read.

Because it was new and cool!

The page I read it on might have been simplifying things, not saying that's exactly how it's implemented. I do know if you play around with subsampling RGB chanels via Photoshop, for example, blue is the least noticeable, red somewhat, green very noticeable.

Always wondered why my 1983 VW van’s instrument cluster has different colored LEDs for various indicators, but a white lightbulb with a blue cap for the high beam indicator.

Learn how to go to the bathroom without sight. Helps a lot.

Ah yes, the touch-n-feel method, I too have stubbed my toe a few too many times!

I'm surprised it has LEDs. The indicators that look like red LEDs in my '93 Nissan are all tiny bulbs, even though red LEDs had existed for a while.

Now I have someone to blame for the white light headlights I see on cars.

I was arguing with a (much smarter) friend about resistors one day. He insisted that if you got the voltage right, you didn't need one. "Dude, LEDs pull amps until they burn, sometimes instantly. You have to either get stupid lucky with current and voltage or you have to use a resistor."

To this day he doesn't believe me. "Dude, take a $1 store light apart, there's a resistor soldered onto the hot lead. Every. Time. Why would China put unneeded parts in there?!"

Underrated

Also allowed for the phosphorus converted amber (PC Amber). A bit lighter in tone than a regular amber which is very orangy. Thermally stable like a white, losing only 10-15% of its lumen output at operating temps vs the regular amber which would see 50% loss. Game changer for emergency lighting.

I was working the night shift in an electronics lab around the time when blue LEDs became cheap. I took apart my desk phone and replaced the red "you have voicemail" LED with a blue one. I always left voicemail in my inbox after that.

the blue led needed a phosphorus layer to get white

​

they found out 2021 a led that does not need it

I use leds to grow weed

samsung 301H is the best you can buy

(*looks around at BattleStation, currently 100% enveloped by blue LED light*)

Hmm. Glad that shit got worked out.

I remember buying blue LED Christmas lights back in the day ... they were so expensive but looked so cool. Now they are stuck in throw-away plastic signs.

Waiting for u/TechConnectify to regale us on the evils of blue LEDs...

Eyes evolved to be most receptive to things of interest.

Things in nature that are green are very interesting. For example, plants. It's probably important to be able to focus on those, especially if you're arboreal.

Things in nature that are yellow or red are also interesting. For example, fruits, blood, and poisonous things.

Things in nature that are blue are much less common. By far, the most prevalent blue thing we encounter is the sky, and that isn't something that we need to focus on.

Researchers hate teaching

Teachers hate researching

Either way in academia you’re forced to do both

LGR has a great video about blue LED https://www.youtube.com/watch?v=yoTALRhAqWc

Also wouldn't the internal resistance of the batteries mean those blue LEDs were drawing less than 5V? 🤔

Facts

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My country has among the highest rates of literacy in the world and our exit signs are green. I don’t think inclusivity has anything to do with exit signs going green, it’s just one of those universal standards in the making.

I remember during a school trip to the science museum (i am 45 now) they had LEDs of all the colours at the time, and the blue one was like "woa"

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Not sure this is true but I have a degree in graphic design and I had a teacher tell me that men see yellows and greens a little bit better than women do because when hunting they'd have to see movement in grass etc. Was told to be aware of over correcting for yellows and greens when colour correcting photos and things.