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Xenon Flashes Can Make New Raspberry Pi 2 Freeze and Reboot
An anonymous reader writes Unfortunately for Raspberry Pi 2 owners who are trying to photograph their devices, ... the Raspberry Pi 2 has been found to be Xenon flash sensitive. Any camera with a Xenon flash aimed at the device is causing the device to freeze for a few seconds before rebooting. The forum thread about the bug is an interesting play-by-play of how the problem was narrowed down.
Hence, even though it looks like the power supply is failing, it could simply be the power supply is turning off due to overcurrent.
No. Covering the regulator chip solves the problem. That means that it is the culprit.
If that was the case, putting a blob of material on the power supply chip (and nothing else) wouldn't remedy the problem – but it does (see the last post on this page.)
How is the Riemann zeta function like Trump rallies? Both have an endless number of trivial zeros.
I am guessing that wrapping it in tinfoil would fix it? I know it works great for stopping the mind-control waves from getting into my head.
This thread shows a quick experiment which confirms it's directly the light which is the cause, not the EM pulse from the capacitor discharge in the flashgun. Chip U16 apparently, which is part of the power regulator.
Years ago when I visited an aquarium I encountered a very strange situation
I was in front of a tank which has 3 electric eels, and in front of the tank there was a 'meter' measuring the power the electric eels were discharging
So I took out my camera (real camera, with powerful Xenon flash light module attached)
Before I pressed the button the Xenon flash was charging (as I said, powerful flash light) and all of a sudden the 'electric meter' in front of the tank indicated that there was an electric discharge from the electric eels
At first I thought it was a coincidence. Then I wanted to take another picture. Again, my Xenon flash light module was charging, and again, there was a jump in the 'electric meter' reading. This second time around I started to suspect that there was a connection in between my Xenon flash light module and the electric eels
The third time around I only use the Xenon flash module. Again I hold it close to the tank, and charge it, and again, the 'electric meter' got another 'shock'. I repeated the experiment the fourth time, fifth time, .... every single time while my Xenon flash module was charging up,. the electric eels inside the tank somehow 'felt' something and gave an electric discharge
I never know the exact reason. My suspicion is that there might be some EMP effect, some wave or some magnetic field, or something like that
What I described happened years ago. I never get the chance to test out my theory
Perhaps someone can test if Xenon flash emits EMP, or not
A 100mW red laser pointer aimed at U16 also triggers it.
Unless you want to claim diode lasers now emit x-rays and low rise time EM pulses... it's light sensitive.
And inspecting U16 closely, it's no surprise. You're not looking at a plastic package but the laser marked underside of a bare die.
He only mentions that it crashes, everybody else answers the question yet he now goes by "Discoverer of the PI2 XENON DEATH FLASH !"
Bingo, that's about what I was going to say. U16 is flip-chip bonded to the circuit board, meaning the naked die is exposed on the bottom. Even if it had a plastic or ceramic cover, it might still be photo sensitive to light getting underneath it. If the underside of the die (flipped, so topside) is really exposed, it basically becomes a silicium solar cell.
TFA found out precisely which chip it is (U16), covering it solves the problem.
The ENIAC Demo Competition
Stop using Flash, it's a persistent vulnerability, and Youtube has an HTML5 video player now.
There's plenty of cases of electronics misbehaving due to exposure to strong light. Glass enveloped diodes (such as signal diodes) can be notorious for it, as can the black plastic encased units if the light is strong enough.
Small bare CoG (Chip on Glass) LCD panels will crash / hang when you use the flash on the camera taking photos of them in operation ( same reason, the controller die is exposed ).
It's not EM-pulse or xrays causing the problem, just good ole silicon junctions being exposed to intense light :)
Really not surprising. The pi2 is pretty crappy hardware. So many better micro computers for projects, not sure why 'geeks' obsess over it.
Oh wow. Random uneducated Pi bashing. Especially considering the device causing the problem is the latest and greatest in small SMPS chip regulators and nothing at all to do with any of the parts that are typically quoted in specs and bitched about by ACs on slashdot.
"Nothing like this will be built again"
I've just had a really amazing experience: a guided tour of the nuclear reactor complex at Torness on the Scottish coast. ... Cameras were verboten -- not because of security, but as an operational precaution. For starters, some embedded controllers in racks in the auxilliary deisel generator control rooms have EPROMs which have been known to be erased by camera flashes in the past, triggering a generator trip ...."
http://www.antipope.org/charli...
Inefficient hardware is sometimes justified by development time.
You can spend many days hand-coding an ideal program for a PIC in ASM. Or you can use an arduino, which takes more power, more space and more money, but can be programmed in a tenth the time by anyone who knows C without needing any esoteric knowledge of harvard architecture and tables of port numbers. If you're doing things a bit more complicated like image processing or networking, the same applies to arduino vs pi: The arduino may be able to do your task if you'll put in the days of programming, but with the pi you're dealing with a familiar linux environment and all the classic libraries are there.