241–250 of 257 posts
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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.
https://medium.com/predict/why-blue-led-earned-nobel-prize-i...
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If I have to guess, support & engineering would be the main force behind LEDs. For example, you have USB port in the bed base, and it does not charge the cellphone, so you call tech support. With LED, it's simple. LED on -> "verify the USB port is not bent or damaged, check your cable, check your cellphone"; LED off -> "verify bed is plugged in, verify outlet has power". Without it? Much harder, especially if you are…
The real questions are: why blue, and why so bright? LED indicators are useful, but they should be red (which comes with the added benefits of being less expensive and drawing less power than blue ones), and shouldn't be bright enough to light the area around them.
Which also means that blue LEDs draw _less_ power than red and green ones, for the same brightness. Thinking about this, this could be a one reason to use them in battery-backed devices.
The "less expensive" part may be was true in the past, but is bogus today: a random search shows $0.01468 for red[0] and $0.01572 for blue[1] in 10K quantity. 0.1 cent is not going to affect your final cost, unless you are into super-cheap devices.
[0] https://www.digikey.com/en/products/detail/beking-optoelectr...
[1] https://www.digikey.com/en/products/detail/beking-optoelectr...
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The real questions are: why blue, and why so bright? LED indicators are useful, but they should be red (which comes with the added benefits of being less expensive and drawing less power than blue ones), and shouldn't be bright enough to light the area around them.
the "why so bright" part is simple: given same current, blue is noticeably brighter. A 5 mA current will make passable red, but flashlight-level blue. If you are old-school designer who got used to red and green LEDs, all your blues would be super bright. I still worry when I see 2K or a 5K resistor next to a LED: "Wait, that's too much resistance and too little current, user is not going to see it... hm, which color…
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the "why so bright" part is simple: given same current, blue is noticeably brighter. A 5 mA current will make passable red, but flashlight-level blue. If you are old-school designer who got used to red and green LEDs, all your blues would be super bright. I still worry when I see 2K or a 5K resistor next to a LED: "Wait, that's too much resistance and too little current, user is not going to see it... hm, which color…
If all of that is true, then I guess I'm just doomed to having to cut the blue LEDs out of the devices I buy forevermore? That's a bit depressing. I was hoping that this was the result of a fad that would eventually pass, eliminating a common irritation from my life.
Your only hope is the transition to post-LED technology.
It looks like there is this secret society working hard on making people suffer in a hotel rooms after long trips. Blue TV indicators, white and blue air condition panels, impossible to cover LEDs that are attached to fire detectors. All of that to make sure the room stays as bright as possible the whole night. I am always impressed with the efficiency of these little, bright, things. In terms of a brightness per cub…
It seems like it should be a no-brainer that if the light can cast shadows, it's too bright to install in a bedroom. I've started traveling with a roll of electrical tape.
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There's a brand on Amazon called LIGHT DIMS that sells differently sized stickers, in both ultra-dim and full-blackout forms, which do _exactly_ what they say on the tin, and it's amazing. I used the ultra-dim for the (white) temp display on my Dyson fan in my bedroom, and the blackout for the brighter-than-the-sun blue LED on my charger brick. Also used the dim one on a smoke detector because my 5-year-old thought i…
I have them. However after a while it became annoying to try to peel the small stickers off the backing, then fumble to center a small sticky thing over the offending LED. so... I use painters tape. I started with the blue kind, but switched to black. Easy to tear or cut, easy to size. electrical tape isn't sticky enough. I choose an appropriate number of layers for the problem. Most lights just need one layer. Somet…
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black gaffer’s tape is perfect for covering LEDs long term without any residue.
maybe i just bought cheap tape, but i've definitely found gaffers tape to leave a residue if left in place for a couple years. especially on electronics that are generating some heat.
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I have them. However after a while it became annoying to try to peel the small stickers off the backing, then fumble to center a small sticky thing over the offending LED. so... I use painters tape. I started with the blue kind, but switched to black. Easy to tear or cut, easy to size. electrical tape isn't sticky enough. I choose an appropriate number of layers for the problem. Most lights just need one layer. Somet…
toothpaste works well and it's easy to wipe off
I couldn't tell if he was serious, kidding, terrible or a genius.
...and your comment asks me those questions too! lol :)
I have multiple layers of blue packing tape over them to deal with it.
I need "sleep hygiene" and for me that involves reducing sensory inputs to as close to zero as I can get.