A nice, simple approach, we think! [Andy] tested the repeatability of the probe, mounted over his CNC-converted Holbrook lathe, reporting a value of 1 um, which seems rather good.

As the proponent here identified as Jonathan has described, the Nook Simple Touch which hails back to 2011 has served as the device for showing train departure schedules.

A simple four-component circuit allows a single I/O line from any microcontroller to sense the states of two capacitive touch sensors. With so many cell phones, PDAs, and MP3 players using touch ...