How could I earth my cat?!

Agreed. :slight_smile:

Coincidentally, I'm doing a class next Thursday at OlyMEGA covering, among other things, the operation, proper or otherwise, of capacitive switches and sensors.

@polymorph

"When I build handheld battery powered devices using capacitive switches, I always put a shield inside the case, if the case is plastic. This increases the parasitic capacitance to the hand holding the device."

You mean - a metallic shield?

My Robocat will have a sort of "fur" above the touch sensor (like a real cat head-back area - where we pet the cats). Do you thing that making it in metal (while putting it in contact with the sensor itself) may do the job?

++++

In my mind, the solution may be:

either to attach a 5 inch / 1 inch aluminium foil to the sensor

or

to attach a large metallic plate to the common ground of the circuts (inside the cat's body)

Please correct me if I am wrong.

Both. Large area of metal inside the cat, and a metal plate for the sensor. It can be foil. Just a wire will not work, there isn't enough capacitance to you.

If you put three strips parallel inside the back of the cat's head, center to sensor, outer two to circuit common, it can be tuned to work without having you hold the cat.

I would use conductive yarn in the lower half of the cat to generate a ground.