Capacitive sensor question MPR21

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1

I have a 4mm steel rod, about 20 cm long, with a plastic handle at the end of it. I am holding it from the plastic handle and using it to touch an elastomer electrode that triggers the capacitive sensor (MPR21). In that scenario (1) the capacitance drops from 150 to 130. I am getting raw data/ debugging code.

Scenario (2) : When I am touching the elastomer electrode only with my naked finger the capacitance drop i am seeing is from 150 to 40.

I am try to find a setup for scenario (1), maybe capacitor to connect to the metallic rod, that will mimic capacitance change that I am getting with the finger touch in Scenario 2. Something that is small to connect to the rod i guess

Any help is appreciated

2

Remove the plastic handle and try again.

A photo of your setup might help us to get a correct image of what you're writing about.

Increasing the surface of the top of the rod to match the electrode size might do the job. It actually depends a lot on the actual form and size of the parts you're using.

3

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