Weird bug alert: A simple xenon camera flash can crash a Raspberry Pi 2

By Shawn Knight
Feb 11, 2015
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  1. The $35 Raspberry Pi 2 launched earlier this month sporting a wealth of upgrades and apparently, one of the most peculiar hardware bugs in recent memory.

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  2. Xtreme gamer

    Xtreme gamer TS Enthusiast Posts: 40   +7

    Reminds me of what a big solar flare could do.
  3. Scshadow

    Scshadow TS Guru Posts: 465   +96

    Thats great and all but isn't that why we encase all our electronics in chassis? I wouldn't just buy one of these chips without some cheapo case to cover it.
    cliffordcooley likes this.
  4. Engineer

    Engineer TS Rookie

    Engineers of Earth your attention please!

    Optosensors 101

    These, quote:
    "...flashes of high-intensity, long-wave light – like those emitted from a laser pointer or a xenon flash from a camera – cause the chip ... regulating the processor core power to momentarily get confused and thus, lose power...."
    via PHOTOELECTRIC emissions induced by (direct) light.

    Like a solar cell, this power regulator IC chip assembly -has semiconductor substrate- emits electric current under certain light -- as most semiconductors do, when light shines on them.
    Seems the IC package has poor-or-nil optical insulation. Certain wavelengths may go through plastic.
    ...plastic shine through? pass-light package...??? (web image)

    And so does ALL alpha, beta, gamma, neutron (ionizing) radiation (from space). Special packaging -non plastic- is called rad-hard.
    If the IC in question is encapsulated/packaged in a plastic injection-mold package, the plastic (black? , above) package may pass certain optical wavelengths, or may even focus/lens effect/ them on the silicon IC die.
    Essentially the whole package-silicon die combo acts as a photo diode, a photo sensor, a photo receiver.
    Optical/laser LED computer mice use LED light to shine on the rotating/moving mice parts and use photo-diode sensors to sense the XY reflected light movement.

    All under-the-microscope semiconductor die probing with needles I did was done under zero-light conditions (black hood) to prevent these always occurring photoelectric currents.
    We did turn all lights off (probing all exposed silicon) to probe voltages & currents correctly, to avoid photoelectric-added contributions. = web image used as example of IC probing under microscope light = needle probes positioning.
    TA! DA!
    mosu likes this.
  5. wiyosaya

    wiyosaya TS Maniac Posts: 931   +238

    It is a similar effect, but not really the same.
    Actually, besides physical protection, the reason most electronics are encased in a chassis is to prevent EM waves from emanating from the device and causing interference with other, nearby electronic devices. Most semiconductors have some sort of plastic or ceramic case around them and would be immune to this effect. It is too bad that the picture of the board is blurry and does not really show any detail of the chip in question.
  6. VitalyT

    VitalyT Russ-Puss Posts: 3,106   +1,376

    No biggie here, placing a piece of black tape on the chip or bottom of the cover will resolve this.
  7. Solar flare couldn't save Krillin's life lol
  8. MannerMauler

    MannerMauler TS Booster Posts: 97   +18

    LOL! I was going to say something like this.

    Well, if you have a 3D printer lying around the house and don't wan't ugly electric tape on your Raspberry PI, get the rough dimensions of the the chip in question and 3D print a cover for it.
  9. Nilbud

    Nilbud TS Enthusiast Posts: 32   +10

    The problem is in the design. If they were that sloppy what other mistakes have they made.
  10. lipe123

    lipe123 TS Evangelist Posts: 632   +163

    They don't manufacture the chips they buy them wholesale from other electronics distributors.

    So really your misguided insult is just.. misguided.
  11. cliffordcooley

    cliffordcooley TS Guardian Fighter Posts: 8,430   +2,822

    It seems some of us have forgotten the initial purpose behind the Raspberry PI. I think any and all mistakes are forgivable, in an electronics valued at only $35. Especially when the initial intended use was for hand-on training in a class room.
    mosu likes this.
  12. wiyosaya

    wiyosaya TS Maniac Posts: 931   +238

    Yes. And just because some dolt figured out that his Raspberry PI 2 needed help taking a selfie and exposed this photoelectric effect flaw does not mean that everyone who uses the PI 2 are going to provide the same assistance to theirs in its selfie taking quest since doing so would make the PI sick.
  13. pieceofSchmitt

    pieceofSchmitt TS Rookie

    Greatest bug ever

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