It did not take long to find a problem with the Raspberry Pi 2. As it turns out, the Pi 2 contains a power regulator chip that is susceptible to bright sources of light. The light will force electrons to move when a metal is struck by enough photons with the correct, per-photon energy, which is its frequency/color, and that will be perceived as a voltage (because it actually does cause a voltage).
In the Raspberry Pi 2, this manifests as a voltage drop and the device immediately powers down. This was first discovered by Peter Onion on the Raspberry Pi forums while he was taking photographs of his Raspberry Pi 2. He noticed that each time he snapped a photo, the Pi would shut down. Liz Upton of the Raspberry Pi Foundation promptly confirmed the issue and wrote a long blog post explaining what actually happens. She borrows Peter's joke from the forum thread, that the Pi 2 is camera shy, and explains that “everyday light sources” will not cause this to happen. She then explains the photoelectric effect, the role of the above pictured U16 chip, and the issue itself.
I definitely appreciate Liz Upton and the Raspberry Pi Foundation, founded on the premise of education, taking the time to explain their bugs from an educational standpoint. That said, it is easy to lose sight of your goal when you have a product to defend, and I am glad that it did not get in the way.
A final note: this will not damage the Pi 2, just cause it to crash and power down. The only real problem is that shutting down your device mid-task will crash your task. If that is a write to the SD card, that will likely corrupt that write.
I didn’t find Liz’s post very
I didn’t find Liz’s post very helpful. She was dismissive and didn’t explain things very well. Her posts in the thread were similar and didn’t contribute positively to the discussion.
Let’s see if the foundation takes this as an opportunity to learn or not.
EH YO DAWG
EH YO DAWG
All chips are photosensitive
All chips are photosensitive to UV. How photosensitive they are is dependant on how thick the chip packaging is, and how intense the light pulse is (a Xenon flash is VERY intense).
Normally, photosensitivity is of minimal concern, as any PCBs will be enclosed in a thick opaque case. The Pi is an exposed PCB, so more vulnerable to photosensitive devices.
This can also occur in other circuits, e.g. barely-synchronised clock generators that speed up or slow down when illuminated. Hows that for a Heisenbug: a circuit that only works right when you open the case up to probe it!
Much ado about nothing for
Much ado about nothing for most of us who use these little beauties.
Just use the Intel Compute
Just use the Intel Compute Stick with Windows 10 in it. Raspberry Pi 2 is defective.
Enjoy your contra revenue,
Enjoy your contra revenue, but ATOM and legacy bloat will not make inroads into the this market, try this the Xenon flash on the Intel device, see if it does the same, if does not, then at least you’ll have a photo of a device that will not be used, with its ATOM bloatware legacy brand. There is a whole computing world outside of the WINTEL umbrella!
A little bit of paint should
A little bit of paint should cure the issue nicely
as would a Marks-a-lot!