Driven shield for touch sensors

[colinives]

I'm working on a product development using a touch wheel based on the ESP32 touch sensors. The ESP32 is very close behind the touch wheel and the grounded meta cover is messing with the sensitivity. I could design in a driven shield plane between the touch sensors and the ESP32 metal case but don't know where I can take an active signal from to use as the shield. I'm assuming a copy of the touch waveform would limit the effects of parasitic capacitance.

Does anyone have an idea where I can pick up a isolated waveform from the ESP32 matching the touch sensing waveform to uncouple the sensors from the ESP32 ground plane.

Thank you.

[colinives]

By the way - I have previously used touch sensors which used a static DC voltage to read the touch sensor - in this situation I drove a plane behind the sensor using a DAC with the average analog sense voltage on the touch pin - this worked very well. The trouble I have with the ESP32 is that it drives a saw-tooth waveform which I can't easily replicate. I thought about using another touch sensor to drive the shield plane but the ESP32 uses time-multiplexing for driving each touch pin.

So, still looking if there is an answer to shielding the touch wheel from the ground of the ESP32.