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Cake day: June 23rd, 2024

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  • USB host devices are cheap and easy to come across. You can use a crap old PC with a fresh OS install, then wipe it. Or an old phone with microUSB OTG. Or a DVD player if you only need the file list (those can usually only open JPGs, GIFs, MP3s, and MPGs or AVIs with one of the video codecs allowed on VCDs/DVDs). Even some microcontrollers will have USB host capabilities and software libraries that will let you get the file list or contents slowly over serial.

    If you’re worried about “killer USBs” (data line zappers), open it and check for capacitors (and antennas in case they use Find My or LoRa for exfiltration but that would be super unlikely). Generating overvoltage inside normal-looking chips is technically possible with charge pumps and embedded capacitors but very expensive to pull off.








  • A good portion of houses in my country never received a telephone line. Straight from arranging calls between phone booths to mobile.

    Before 1989, the state monopoly had an installation backlog of several years (you could only get a line fast if you were high up in the party or had friends at the telco), high monthly fees and was woefully behind on tech: there was no digital voice equipment on the whole network, while the US’s Bell trunk network had all-digital audio by 1970. Even until like 1980, in regional towns of 30k-50k, they required you to speak to operators for out-of-town calls. After 1990, the company privatized but it was still prohibitively expensive to get a line set up, as so much money needed to be spent to belatedly bring the network into the digital era. The monopoly ended around 2000 and prices went down but by that point, people saw the dawn of mobile and didn’t want to pay for a new phone line anymore.




  • ChaoticNeutralCzech@feddit.orgtoLemmy Shitpost@lemmy.worldlightbulbs
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    3 days ago

    The wavelength has negligible effect on shadow geometry (yes, there is chromatic aberration, refraction, interference but those are very minor in normal lighting, you need special prisms, tiny slits and perhaps lasers to really observe them). What do you even mean?

    Also, sunlight (6000K) and daylight (6500K) is pretty much the same color because direct sunlight is >90 % of daylight (the rest is the blue sky and white clouds).





  • I’m not saying it’s a bad idea, I have a red bulb too. It’s “handmade” by removing thick red rubber from a “golf ball” decorative 7W CFL and stretching it over a similarly-sized 6W 2700K LED that has instant start and higher light output (not to mention, the taut rubber won’t send glass ball shards into a mercury-vapor-filled tube if it happens to fall). It is not as monochromatic as pure red LEDs, I think it’s close to what the phosphor-based red ones emit (with a lower efficiency of course since I discard the blue and green while they turn almost all blue into red and no green) and those are marketed as cicardian too. I have to avoid looking straight into it though: the pupil is wide open because rods don’t react strongly to red light so long-wavelength (red) cones get massively overloaded and I see a green spot for a while.


  • ChaoticNeutralCzech@feddit.orgtoLemmy Shitpost@lemmy.worldlightbulbs
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    3 days ago

    The difference is not as pronounced as in the picture. If you’re used to 4000K as neutral white, yellowish white is 3000K, amber-ish white is 2700K. Only below the temperature of fire (cca 1500K) is when blue fully disappears and you get actual orange or red. And pure yellow is not a possible black body (incandescence) spectrum (that is, it does not correspond to any color temperature) so even though you can set an RGB bulb to that, buy monochromatic yellow LEDs or go under a low-pressure sodium vapor lamp, such lighting feels unnatural.


  • ChaoticNeutralCzech@feddit.orgtoLemmy Shitpost@lemmy.worldlightbulbs
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    3 days ago

    Warm white is usually 1800 K to 3000 K. What you showed is less Kelvin than the color temperature of fire (1500 K). We don’t have a color temperature word for that, but “red” works. Of course, such light has no blue component (helps control the cicardian cycle) and is pretty much monochromatic with CRI of <5.