3 ms·

A Xenon flash used to freeze the Pi 2.

by cyberjunkie 7y ago

SudoEpoch 7y ago
Helium will also cause it to stop working
- wereHamster 7y ago
  Helium will make the iPhone gyro stop working for a few days.
  - Redoubts 7y ago
    Almost forgot how cool MEMS are
  - baq 7y ago
    the whole thing, actually, not just the gyro. the clock is nanomechanical and helium breaks it, apparently. the newer models have a version that fixed that particular problem. it was in the fine print in the manual somewhere.
segfaultbuserr 7y ago
I don't know why it became such a piece of breaking news. When a current flows through a p&n junction, photons are emitted (and an LED is just a diode that happens to emit photons at the wavelengths of visible light). And it works in both ways, if you hit a p&n junction with photons, you produce a current, not only LEDs - any diode will do that, they're all potential photodiodes, it's just that some are more sensitive than others. You can cause a lot of chips to reset if you shine a bright beam of light to its exposed die, a common way to test chips. It's also one reason (in addition to cost) that most diodes are sealed in plastic package, not glass package. Fun experiment: buy some 1N4148 small-signal diodes in glass package, connect it to a Darlington-pair transistor amplifier, and shoot the flashlight, you'll see some funny thing on the oscilloscope.
- nrclark 7y ago
  I think the newsworthy part of all that wasn't the physics involved, but more the design-choices on the Rpi 2. Putting a light-sensitive chip (I think it was a wafer-scale package with no casing) on a board that's intended for use outside of an enclosure was a really big oversight.
  - segfaultbuserr 7y ago
    > a really big oversight. I agree.
- avian 7y ago
  > I don't know why it became such a piece of breaking news. Popular buzzword (Raspberry Pi), surprising unexpected outcome (most consumer electronics people are familiar with don’t react to light), manufactured outrage/schadenfreude (look how they screwed this up!)
  - segfaultbuserr 7y ago
    > Popular buzzword + Surprising unexpected outcome Good analysis. In both cases, I see the popular press reports them in personified language, "Xenon Death Flash, or Why the Raspberry Pi 2 is Camera Shy", and "Why the new iPhone is Allergic to Helium". If we replace "Raspberry Pi 2" with "semiconductor p&n junctions", and replace "new iPhone" with "MEMS oscillators", it probably won't be news anymore. > manufactured outrage/schadenfreude An interesting case as well. I see both incidents as undesirable side-effects that better to be prevented, but I don't think they are major design flaws.
    - Dylan16807 7y ago
      Your version doesn't just remove any personification, it gets rid of the entire concept that these are exposed parts on consumer devices causing them to fail. So sure, that version would get no notice.
tallanvor 7y ago
One of my professors told a story of reporters crashing one of AT&T's new digital exchanges because their camera flashes erased some of the EPROMS used in the system.

A Xenon flash used to freeze the Pi 2.

SudoEpoch 7y ago

Helium will also cause it to stop working

wereHamster 7y ago
Helium will make the iPhone gyro stop working for a few days.
- Redoubts 7y ago
  Almost forgot how cool MEMS are
- baq 7y ago
  the whole thing, actually, not just the gyro. the clock is nanomechanical and helium breaks it, apparently. the newer models have a version that fixed that particular problem. it was in the fine print in the manual somewhere.

segfaultbuserr 7y ago

I don't know why it became such a piece of breaking news. When a current flows through a p&n junction, photons are emitted (and an LED is just a diode that happens to emit photons at the wavelengths of visible light). And it works in both ways, if you hit a p&n junction with photons, you produce a current, not only LEDs - any diode will do that, they're all potential photodiodes, it's just that some are more sensitive than others. You can cause a lot of chips to reset if you shine a bright beam of light to its exposed die, a common way to test chips. It's also one reason (in addition to cost) that most diodes are sealed in plastic package, not glass package. Fun experiment: buy some 1N4148 small-signal diodes in glass package, connect it to a Darlington-pair transistor amplifier, and shoot the flashlight, you'll see some funny thing on the oscilloscope.

nrclark 7y ago
I think the newsworthy part of all that wasn't the physics involved, but more the design-choices on the Rpi 2. Putting a light-sensitive chip (I think it was a wafer-scale package with no casing) on a board that's intended for use outside of an enclosure was a really big oversight.
- segfaultbuserr 7y ago
  > a really big oversight. I agree.
avian 7y ago
> I don't know why it became such a piece of breaking news. Popular buzzword (Raspberry Pi), surprising unexpected outcome (most consumer electronics people are familiar with don’t react to light), manufactured outrage/schadenfreude (look how they screwed this up!)
- segfaultbuserr 7y ago
  > Popular buzzword + Surprising unexpected outcome Good analysis. In both cases, I see the popular press reports them in personified language, "Xenon Death Flash, or Why the Raspberry Pi 2 is Camera Shy", and "Why the new iPhone is Allergic to Helium". If we replace "Raspberry Pi 2" with "semiconductor p&n junctions", and replace "new iPhone" with "MEMS oscillators", it probably won't be news anymore. > manufactured outrage/schadenfreude An interesting case as well. I see both incidents as undesirable side-effects that better to be prevented, but I don't think they are major design flaws.
  - Dylan16807 7y ago
    Your version doesn't just remove any personification, it gets rid of the entire concept that these are exposed parts on consumer devices causing them to fail. So sure, that version would get no notice.

tallanvor 7y ago

One of my professors told a story of reporters crashing one of AT&T's new digital exchanges because their camera flashes erased some of the EPROMS used in the system.