Will an LED blink if noone is looking?

Using Arduino General Electronics
6

I've since noticed two things:

  1. Probing Gnd and pin 5 shows 0v, 4.88v in time with the 2-sec delays. Probing pin 5 to the center tap of the divider shows -0.02v at all times... which is to say, probably near the error threshold of the meter. No idea why that is.

  2. Moving the Tiny off this breadboard (set up as an incubator solely for use with AVRdude) to the breadboard with the intended project, it behaves as expected. Of course, its final job is not to just blink red and green. The project board has an audio input that fires a transistor when the signal is over a threshold, pulling the INT0 pin low, triggering an interrupt, turning the LED green, and turning on a power amp. This is naturally a much longer program. At any rate, on a board with a half dozen op-amps, a few transistors, and a bunch of other parts, it seems to behave. Maybe because of the multi-output transformer (-12, +12, +5) that is running that board? Not entirely sure.

So, this is more or less solved in the immediate sense, but I still can't explain what happened.