Vintage capacitive switch

Question

I have this switch from a Philips Electronic 212 turntable. It’s simply two metal pieces, one a ring and the other a button-like center. I’m not sure, but I think it is a capacitive sensor or button.

I need a circuit to connect this switch to an Arduino. When my finger touches both metal parts, the Arduino should read a digital HIGH and when I release a LOW.

Perhaps this can be read from analog pins too.

I can code whatever this needs to work, but I don’t know what the circuit for something like this would look like.

My code would probably depend on the circuit being connected to a digital pin or an analog one.

I’m attaching pictures of the switch.

Answer 1

This is a resistive touch switch; it uses the resistance of the skin to close a circuit, originally probably enabling a base-emitter current to flow in a (Darlington) BJT that does the actual switching.

There are many circuits on the interwebs for this, just google "resistive touch switch circuit".

Answer 2

As fond as I am of the old school Darlington- or comparator-based touch sensor circuits - which is what it looks like your device originally connected to - capacitive touch switch ICs are probably simpler and cheaper and have many useful features baked in. Connect both the center and ring or just the center and ground the ring if you like. Take a look on any of the big reputable electronics sites, you'll find dozens of options.