🚀 go-pugleaf

I tried this experiment when I first read (in Popular electronics) about
using capacitors in place of piezo disks for electronic drums. 

	Basically, what I wanted to do was rig a device that could be
mounted to the INSIDE of a 1.5" wooden door, and when somebody knocks on the
OUTSIDE, it produces a sound...

e.g.:

Knock. TICK
Knock. TICK     (they knock, it makes a much louder TICK! or whatever.

	I managed to get it to work, but only if the sensor was on the outside
and one knocked directly on it- not much better than a doorbell. what could I
use as a sensor that will work on the inside to detect a "normal" knock?
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