5

I've seen recent articles on the Raspberry Pi 2 being affected by a light source (http://www.raspberrypi.org/forums/viewtopic.php?f=28&t=99042) . Apparently the cause is in the power regulation circuit of the Pi.

Does the Pi B+ have the same problem, or is the circuit sufficiently different that it does not have the affected component?

  • First I've heard of this. I have not seen it mentioned on the raspberrypi.org forums. Have you a source? – joan Feb 8 '15 at 22:52
  • @joan: raspberrypi.org/forums/viewtopic.php?f=28&t=99042 . I will add it to the question – John Smith Feb 8 '15 at 22:54
  • 3
    I didn't read that thread as I thought it was a joke (because of the title). I have just skimmed through. My PI 2 locked up when I took a flash photo. A B+ was unaffected. – joan Feb 8 '15 at 23:05
  • Wow. Guess that got skipped in QC. I've noticed a B and a B+ that would often reset an I2C device the moment something was unplugged on the same (household) circuit. – goldilocks Feb 8 '15 at 23:10
  • All semiconductors are light sensitive. (I discovered this the hard way - more than 50 years ago when I scraped the paint off my 1st transistor - in those days transistors were in little glass tubes). The encapsulation keeps light away, but surface mount components are not designed to be exposed to the environment. – Milliways Feb 8 '15 at 23:59
2

According to the Raspberry Pi Foundation, the problem lies with component U16 in the power supply. This is not a component used on previous models.

The explanation is given here.

This also explains that the problem is a photoelectric effect caused by specific long light wavelengths, particularly Xenon camera flash guns. So other light sources have no effect.

0

I wouldn't consider this authoritative but the following article suggests it is "light" sensitive and not EMF as I had originally thought. Previous models are not affected.

http://arstechnica.com/security/2015/02/just-released-raspberry-pi-2-can-be-dosed-by-bright-flashes-of-light/

  • 1
    but why are previous models not affected? Component types? Circuit changes? – John Smith Feb 10 '15 at 23:25

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.