Olin Lathrop wrote:
> > I have an AVR board with a switch shorting a pin to ground, and
> > the internal pull up enabled. I found out the resistance was
> > less than that of my body and I can make it think the button
> > is pressed by touching the pad the switch is soldered too. I
> > don't even have to touch the ground plane at the same time.
>
> Your body is picking up power line hum or other noise.
Hmmm... I didn't think of that. Should have been obvious as it's
only about a foot away from a computer & monitor.

The AVR pull up is (was :) VERY weak, though. I think it's around
100K but I'm not sure. My volt meter also set it off. I'm not sure
what it's resistance is, but it's a cheap Radio Shack one so it's
probably not too high.

> > For some reason the pull up suddenly stopped working.
> > Strange.
> Yeah, when you zapped it with static from your finger.
Probably. I should know better than touching electronics after
walking around on carpet, but it was just so cool. Touch the pad
- oooo a little red light comes on!

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