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Comment by mrweasel | Hacker News Reader

Why is it that manufacturers go for blue or bright white LED indicators? I assume that they are cheap enough that it doesn't matter, but green would probably still be slightly cheaper.

We have a USB charger that cannot be used in a bedroom, not that you should, but it can light up an entire room. Why not just have a tiny green LED? Apple is really good about not using bright LEDs in their product, or really any LED indicators (there might still be one in the magsafe). So why is it that every cheap random fly by night Chinese manufacturer feel the need to add a tiny blue torch to their products?

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This is how I remember it: For some time LEDs were red, yellow or green. Power LEDs were almost universally red. You can see this on devices from the homecomputer era (Amigas, Ataris, etc.). I'm not sure if red was chosen for technical reasons (red LEDs have the lowest voltage drop), maybe economical reasons or it was already a convention before LEDs became available.

Anyway, when blue LEDs became feasible they were the epitome of cool and every device had to have them. So in my opinion it was a fashion trend that stuck.

Indeed, red was the first visible LED color to be practical in production. Blue came much later.

Blue LEDs were deemed a huge breakthrough at the time; they enabled full-colour LED displays (think large panels viewed from a distance) by adding the long-missing B in the RGB.

Indeed, and they are also the basis of single element white LEDs, which are a blue led covered by a white phosphor. The inventor of the bright blue led worked for a chemical company that made phosphors, and invented the white one as well.

They also enabled bueray DVDs.

Enough of a breakthrough to be worthy of a Nobel prize, even:

https://medium.com/predict/why-blue-led-earned-nobel-prize-i...

> the epitome of cool

I remember being wowed by the blue power LEDs on VA Linux servers in the early or mid 2000s! Now any stock photo of a server room is covered with blue lights.

Speculation: Perhaps they are trying to distinguish themselves from the "cheaper" products by using the "new" blue LEDs? IIRC the technology for them was figured out much later than green or red, so maybe there is a bit of leftover "futuristic" feel to them.

The last time I saw a blue room-illuminator was on an ancient Belkin Bluetooth dongle. IMO the practice has gone out of style with most name brands (including Apple).

It's basically this, yes. Blue LEDs were such a game-changer that the inventor won a Nobel prize for it. When they became cheap enough to use in consumer electronics, manufacturers went absolutely nuts and put them in everything as a sort of whiz-bang look-what-we-can-do thing. But since everyone did that, they stopped feeling distinctive almost immediately. The only designers still using them for indicators are the ones who can't tell when a fad is over. They're still very important technology for LED light bulbs; white LEDs are blue LEDs with a yellow phosphor.

ETA: I'll add that it takes real time, effort, and crucially taste to get an LED indicator to not be a retina-searing nuisance. You have to be willing to devote time to getting it right, and for someone just trying to pump out cheap units at volume, that's not an easy sell.

I remember thinking the blue led on the PS2 was so cool when it first came out.

I remember, it was extremely cool! 23 years later the novelty has worn off a bit.

Looking at flashlight runtimes on battery, it seems like white LEDs (blue with a phosphor) or blue, are much more efficient per lumen than any other color. Perhaps that could be a reason as well? I'd generally prefer green and red.

I expect that has to do with the properties of the human eye, and the fact that the lumen is defined in terms of those properties. I doubt white LEDs are significantly more efficient than any other color in terms of EM flux per watt, but a relatively large proportion of those emissions are at wavelengths to which the retina is sensitive.

> Why is it that manufacturers go for blue or bright white LED indicators?

I don't know but I'm sure allergic to red. I don't understand why so many devices are using red for standby or even to indicate work (I'm looking at you Raspberry Pi).

To me red is "blood" and blood is "bad". Red means error.

Thankfully some devices, like ethernet switches, are using proper colors: green for trafic, orange for "degraded" link (say 100 Mbps on a gigabit switch). I look at the rack and there are tens of LEDs and it's all blue, green, orange. That's correct. Zero red. That's what I expect when everything is working fine.

Orange for standby is acceptable, I guess.

I like blue. Maybe not bright blue but blue is way better than red IMO.

If I see something red, it better be an error: alarm / motion detector / garage door opened / whatever.

Funny, I imagine you're pretty young?

For us oldies red is just the normal LED colour since in the 80s this was the only colour that was available. Our alarm clocks, microwave displays, indicator lights and even some watches and calculators used red LEDs :)

For me red is pomegranates. A very happy colour.

I suppose that colour preferences may be cultural.

I don't know: red seems to be the color of blood, a bad omen to witness. Green is the color of grass, quite okay. Blue is the color of the sky and yellow of the sun. Colors are not absolutely random I think, and could just as well cross cultural boundaries. But maybe "preferences" are sort of subjective: China really likes yellow and red a lot more than France for instance, even if they have the same meaning sort of (the red communist flag does suggest the blood of the people for both culture, for instance, and yellow does seem "valuable" for both as well - we like our gold statues just as much in both).

Red doesn't bother the eyes in a dark environment.

It's not just bothersome; red is in the sweet spot of visible but doesn't interfere with your night vision.

There's a reason lots of camping lights have a red mode, and why astronomers use it exclusively while observing.

https://stellarium-labs.com/blog/nightmode/

Unfortunately it does bother me. It's so bad I must turn off or at least cover red LEDs before I can sleep. E.g. TVs. Thankfully for our bedroom TV we recently switched to a Sony TV recently which doesn't seem to have a standby LED at all – such a godsend as it can be turned off simply by pressing the remote and it turns off without a standby LED.

It's not bothering your eyes. It's bothering your brain. In a dark room a red light will not make your eyes lose their ability to quickly see in the dark like the other colors do.

> proper colors: green for trafic, orange for "degraded"

I’m color blind and hate this color choice. Damn near impossible to tell apart. Around 8% of men would agree.

Yeah my external HDD has a blue LED that's so ridiculously bright it lights up the whole room and puts a really bright blue spot on the other side of the room.

I tried covering it with a post it (several layers) and after a month I noticed that the yellow colour had whitened completely where the LED is. Probably contains an unhealthy level of UV as well. Yuck.

I tried opening it up to replace the LED but it's clipped somehow. Very hard to open without damaging it.

I have good experience with drilling a small hole in the side of the housing and through the LED. You need to aim well. Its not a good technique for all annoying LEDs.

Sometimes the indicator LED acts as a voltage reference for some circuit. In that case, destroying it is a bad idea.

Also, I think most hotels would object ;-)

Only the cheapest of cheap electronics would use an LED as a reference.

Also, I dont bring a drill to a hotel.

Because a good number of customer service calls come from people who have a device plugged into a dead outlet. The led at least tells you the device is getting power. It can also indicate whether any internal fuses/breakers have tripped. And many manufacturers blink that one led for error codes and such. They have a purpose, and can generally be blocked by any bit of cheap tape.

That doesn't explain why they're blue - which is a much brighter and more intense LED color then green or red.

The craziest one is the subwoofer my parents bought for their home theater - this is a device you would exclusively use in a darkened room while watching movies...and it has a full size eye-searing 3mm LED to indicate "power on" (it's been electrical taped over for about a decade now).

My theory is that blue lights stand out more in Amazon search results.

I think blue just feels "modern". Red LEDs feel like they belong to the 80's, and green to around 2000. While white feels "clean".

I agree 1,000% that they're ridiculous though. But the colors are definitely about achieving an up-to-date "look".

Blue just feels tacky and cheap to me. Maybe "modern" and "cheap" are just the same thing.

I think we are rounding another curve where the blue will start to fade away and white will be the new color

There was a time when industry did not know how to produce blue or white LEDs, only red, orange, yellow and green ones, so you see, red, orange, yellow or green LEDs are old tech, and consequently not suitable for our magnificent product.

They could make them decaying blue in a white matted plastic rather than piercing your eye and a wall bs. I tape all these useless components on everything I have. They are useless, because people tape them or turn off and then can’t test the outlet power loss anyway.

I wish I lived in a world without marketing idiots so much.

> We have a USB charger that cannot be used in a bedroom, not that you should, but it can light up an entire room.

Had the same issue, thankfully a piece of black duct tape was heavy enough to fix the issue. Really annoying to have a device which is essentially unusable out of the box.

> Apple is really good about not using bright LEDs in their product, or really any LED indicators (there might still be one in the magsafe).

They do have an indicator led on the magsafe plug, which is either amber or green, and is pretty bright but easy to unplug.

The old MBPs also used to have a white but pretty dimmed led "breathing" during sleep, it was quite pretty unless you wanted to sleep then it was annoying. If easy enough to put a thing in front.

I also have a ugreen mini dock with a white led, no idea why. It's a passive dock, if it's plugged in it's on, I don't need to have a reminder.

I think the latest MBP M1/2 also have it still.

My guess is that next to zero actual thought goes into the design and production of most items these days. Companies are getting cheaply designed cad files and whacking them onto an assembly line and shitting them out into a shipping container bound for a nameless Amazon sellers page.

AppleTV 4k has super bright white led on the front (outwards to user) while the device is on. So annoying!

Don’t want to dismiss your complaint, but I find mine generally is not even that noticeable considering the main function of the Apple TV is playing media on my tv that lights up the whole room. What annoys you about it?

It's a white light sitting below my tv constantly shining a light at my face. What is the point of it? I already know the thing is powered on because I powered it on and it's playing a movie or whatever. Facing it backwards helps but then all the wires are exposed and look ugly.

Anyway, it wasn't really a strong complaint, but parent poster said Apple generally doesn't do it, but I have it on at least two generations of apple tv.

As someone with a fair bit of astigmatism... a visble white dot maybe 6 inches from the edge of the TV is just about worst case for making any sort of dark scene look blurry.

This is why you get a mount for the AppleTV and mount it behind the tv itself. I use a total mount, the same one sold in apple retail stores.

I would prefer that manufacturers use the traffic light colour scheme:

* Red: stopped or off (preferably dimmed of completely off)

* Yellow/Amber: startup or error state in which the device needs intervention

* Blue/Green: running properly

For battery powered devices, red should be “charging”.

You don't want to make things indistinguishable for the color-blind.

That's an important consideration, for sure.

What would be an appropriate set of color choices then?

Constant, blinking slow, blinking fast, Morse code blinking

Like traffic lights, physically separate can be different colors. Red-green colorblindness is most common though, so your easiest bet is to only pick colors where red or green is always zero, then vary the amount the other and blue. If choosing LEDs, most are single-frequency, so ignoring anything orange or lower frequencies removes most of the redundant choices; leaves green, yellow, blue, violet. They're plenty of good websites out there for details.

>Blue/Green: running properly

this would be redundant as you'd know that the device is running in most cases

The MagSafe cable still has an LED in it, it's green when you're fully charged and orange when it's charging.

But I agree, Apple is good about not annoying you with LEDs.

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