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Flash can cause camera-shy Raspberry Pi 2 to crash

The microcomputer designed to get kids interested in coding powers down when hit with high-intensity, long-wave flashes from cameras.

Don Reisinger
Former CNET contributor Don Reisinger is a technology columnist who has covered everything from HDTVs to computers to Flowbee Haircut Systems. Besides his work with CNET, Don's work has been featured in a variety of other publications including PC World and a host of Ziff-Davis publications.
Don Reisinger
3 min read

Here's the Raspberry Pi 2 board itself. The latest edition of the computer designed to get kids into coding has a slight defect that causes it to blink every time it's hit with a high-intensity camera flash. Luke Westaway/CNET

Raspberry Pi 2, the latest edition of the cheap computer designed to get kids into coding, has a slight defect that causes it to blink every time it's hit with a high-intensity camera flash.

Some Raspberry Pi 2 owners discovered over the weekend that when they photographed the device with a flash, it would turn off. Since then, Raspberry Pi Foundation employees have been analyzing the device to see what causes the issue, and according to a company spokeswoman, it happens only under very specific conditions.

"Flashes of high-intensity, long-wave light -- so laser pointers or xenon flashes in cameras -- cause the device that is responsible for regulating the processor core power (it's the chip marked U16 in the silkscreening on your Pi 2, between the USB power supply and the HDMI port -- you can recognise it because it's a bit shinier than the components around it) to get confused and make the core voltage drop," Raspberry Pi Foundation spokeswoman Liz Upton wrote in a blog post on Monday. "Importantly, it's ONLY really high-intensity bursts like xenon flashes and laser pointers that will cause the issue. Other bright lights -- even camera flashes using other technologies -- won't set it off."

Raspberry Pi 2 launched earlier this month for $35 . Like its predecessor, the microcomputer is a barebones device designed for people -- especially kids -- who want to learn coding. Since its launch in 2012, the Raspberry Pi has proven extremely popular with DIYers and a wide range of technologies have come out of it, including everything from gaming devices to media centers and wireless controllers for speakers. Millions of units have been sold since inception.

Since Raspberry Pi is designed to be open to users and allow them to do whatever they want, the possibilities for application in the real world are limited only by the device's components.

On that front, Raspberry Pi 2 comes with a solid slate of components, including a quad-core Broadcom CPU, a dual-core GPU, and 1GB of RAM. The new version has six times more power than the previous model, according to the Foundation.

While earlier versions of Raspberry Pi were not camera shy, Upton said that the issue relates to a photoelectric effect on the device's U16 processor core power regulator. The bare silicon die is hit by the high-intensity light and the semiconductor material emits electrons, causing the device to power down.

"Silicon junctions (the types that are responsible for making diodes and transistors and other such electronic miracles function) can be 'upset' by this photoelectric effect if it is large enough (i.e. if enough light of the right energy [i.e. colour] is fired at them)," Upton says. "This seems to be what is happening to our power supply chip - somewhere in the complex silicon chip circuitry there are some transistors or diodes that malfunction when hit by high energy bursts of light, causing the power supply to 'drop out', so the Pi reboots."

Luckily for Raspberry Pi 2 owners, the issue does not appear to cause permanent damage. In addition, it only occurs under very specific circumstances, so older non-Xenon flashes and direct sunlight will not cause the issue, Upton says.

Raspberry Pi Foundation has found a quick fix for addressing the problem, saying that simply covering the chip can stop the issue from happening. The organization recommends moldable glue Sugru or putty-like Blu-Tak will stop it from powering down even if it's hit with a high-intensity flash.

Watch this: Raspberry Pi projects