New on Anelok TV: capacitive sensing

Werner Almesberger werner at
Tue Apr 29 17:47:23 EDT 2014

To evaluate the possiblity of using a capacitive slider instead of
the mechanical wheel in Anelok, I made a very simple slider and
gave it a try.

Here are some first impressions:

Design files and the demo application are here:

The sensor code is here:

I used the Y-Box for this since the right pins happen to be
conveniently accessible.

The result doesn't look too bad. While the sensor wouldn't be usable
in this form, I'm pleased with the range of values I'm obtaining
(see below) and the overall quality of the signal.

Counts	Event
-------	--------------------------
< 10500	No finger
  10620	Normal touch on the right
  10860	Normal touch on the left
> 11050	Strong press on the left

I could probably tune this to even better sensitivity.

The environment also contributes a bit to the measurement. E.g., I
had to raise all the thresholds by about 50 counts when moving the
sensor from table to monitor.

- Werner

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