Of all the constant light sources, direct sunlight produces the most pronounced change in 1v2 core voltage (which is to be expected with a massively broad-band, high intensity source) but this is far more benign than the instantaneous change caused by a xenon lamp.Ravenous wrote:Trivia question: is it a flash (ie a brief transient) or can a constant but very high intensity light cause this? I'm thinking of the step response in the control circuits of the regulator chip - will it be stable under a sustained light level? If so, sunlight is less likely to be a serious problem.
(Just a thought. Not that it matters much to most of us.)
The discharge time for a lamp is of the order of 10s of microseconds which interferes with the control loop response in addition to the output voltage. I can imagine the same result with a narrow point source - lasers reflecting off various surfaces near the device causing instantaneous fluctuations.
The resulting dip in the 1v2 line (as displayed prominently in the blog post) is what causes the Pi to crash/brownout/reboot.