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Comment by matgessel | Hacker News Reader

My favorite tape for attenuating bright or annoying LEDs is ruby litho tape (3M Lithographers Tape 616). It passes deep red light and dims bright green and blue LEDs to a faint red. It's perfect for green/amber status lights; the green "OK" is mostly blocked and the amber "Problem" shines through. Removes easily without leaving a mark.

https://www.3m.com/3M/en_US/p/d/b40068069/

https://www.amazon.com/3M-Lithographers-0-375-width-length/d...

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My second favorite tape is Honda's spicy rodent deterrent tape. It's made in Japan with capsaicin. It's not cheap, but much cheaper than an wiring repair at an auto shop*. The lowest price I was able to find seemed be be a dealer in Colorado … until I created an account, went through the order and saw the ~$20 S&H. The best deal including shipping was from the same dealer on eBay — no S&H charge.

https://www.teraokatape.co.jp/english/products/no/no300/data...

Rats chewed through wiring in my car on two occasions. Both occasions were in cold weather and the chewed wires were above shelf-like spots in the engine compartment. One was a transmission solenoid wire and the other was the ignition wire in the main harness above the wheel well. In both cases I was able to self-repair by popping the pins out of the wiring connectors and soldering new leads (pig tails) to the pins. YouTube has several videos explaining the process.

Fun fact: rubylith tape was one of the tapes used to "tape out" early chip designs.

Wait, what? I thought the term "tape out" came from the original process whereby the design would be exported to a data tape for transport to the fab.

What do you think they did in the early days, before such things as data tapes or anything that could read them even existed? It used to be all photo masks, and the masters for those photo masks were made with... tape. Usually rubylith. Always by hand.

> the original process

The "original process" of integrated circuit design was cutting rubylith - this was well into the 70s. The venerable MOS 6502 was done this way as was the Intel 8008.

The verb tapeout was used for litho prior to integrated circuits though, back into the 40s.

But you should realize that PCBs and integrated circuits predate generally available computers and digital data storage.

> exported to a data tape for transport to the fab.

There was an article in The Register years ago that promulgated this misattribution - it was generally never a reliable source, no exception here.

That's why IC layouts used to be called "floor plans". They were floor-sized drawings on which people laid out lines with tape. The floor plan was then photographed from above and color-separated into masks.

"Back into the 40s?" ICs aren't that old.

Printed circuit boards have long been laid out by hand, and sometimes still are, but they're not usually photo-reduced. They're laid out at full scale.

> "Back into the 40s?" ICs aren't that old.

I think the parent is saying that the verb 'tapeout' goes back to litho processes before litho's use in IC production, not that IC production went back to the 40s.

Can confirm. When I was a kid I was an offset printer. We used rubylith for that. Then I learned PC design. Rubylith again. Then I went to work for an IC design firm. No rubylith there; our product produced Gerber file tapes. But the old-timers still called it "taping out" because it used rubylith before the Gerber days.

Good to know. I wasn’t even aware such a tape existed when I covered some powerful blue leds that were interfering with my sleep. Sometimes I wonder if the correct leds are used for status leds. The blue LEDs Im talking about were lighting up a whole wall at night and from somewhat useful they turned to a nuisance of sorts.

Blue leds are an obviously incorrect choice; they are only used because are novel and trendy (well, I guess they used to be novel and trendy, anyway). Human color vision is the least sensitive to blue light – but human low-light vision is the most sensitive to it!

As someone who is red/green colour blind, I disagree that they are an incorrect choice.

Annoying at night yes. But wherever they are used I can finally make out the difference between an ok/nok status.

Ah, I’m red/green blind too but most blue leds in electronics don’t seem to have a status function beyond "on/off", they’re there just to look futuristic.

Yeah my phone charger has a super bright blue led in it. It's kept in a draw at night as the entire room lights up. I keep meaning to cut out the led.

my best guess for blue lights is that it's one of the ones with higher energy efficiency and red/yellow would indicate problems.

One of my HP switches have setting for that, you can choose a time interval when the lights should be dimmed or turned off.

Thankfully the era of "slap blue led so the hardware looks modern" is over (back then blue leds were new thing and pretty expensive), but some devices still go too bright.

Status LEDs should be only bright enough to be obvious, they should be frosted/opaque, and should only be Red, Orange, Yellow, or Green.

Retina searing water-clear blue and violet LEDS have no business being used for any status light anywhere. Even in bright light, the better choice would be bright green due to the eye's sensitivity being maximum in the green.

Is that Amazon listing legit? Price seems to be significantly cheaper than anywhere else

Good question. I Last bought a 60 yard roll for $12.50; sold directly by Amazon. Looks like it's about $14 now. Here's the listing: https://www.amazon.com/gp/product/B00JX9D6I2/

The listing in the parent comment is for 5 yards.

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