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THE RASPBERRY Pi 2 has a bug where it will crash when subject to xenon flashes or laser light, due to an unexpected photoelectric effect.
According to the Raspberry Pi Foundation, the Raspberry Pi 2 is “camera-shy” because the chip that regulates the process core power is made of a semiconductor material that is subject to a photoelectric effect when hit with high-intensity, long-wave light.
The photoelectric effect, simply, is when metals or semiconductors emit electrons when hit by light.
“Semiconductors, like metals, have free electrons which can be ‘knocked off’ by photons. Photodiodes, solar cells and phototransistors all use this effect to function,” explained the Raspberry Pi foundation.
This means the chip malfunctions when hit with laser pointers or xenon camera flashes, causing the core voltage to drop, and thus the entire unit to shut down. The same effect is not observed with other light sources, such as sunlight or LED flash lights.
The component affected is silkscreened with the text U16, and is located between the USB power supply and the HDMI port on the Raspberry Pi 2.
According to the Raspberry Pi Foundation, while “flashing” the Pi 2 has not been shown to cause any real damage, it is not recommended to do so since a crash can corrupt the SD card. It is investigating ways to immunise future production Pi 2 units from the issue.
In the meantime, it is possible to protect the Pi 2 by covering the U16 chip using either Sugru or Blu-Tak. Cover the entire component, including the sides. Or put the Pi 2 in an opaque case.