The i2c is received by ESP32S3, and the output is output to the main body of the instrument via ESP-NOW.

An illuminated push-switch was installed, but it took a lot of time and effort to drill the holes in the stainless steel.

The touch sensor and its control board will be mounted bare on the top of the angle, while the MCU and battery will be assembled on the frame in advance and glued to the bottom of the angle with double-sided tape.

When the Trill control board is mounted on the angle material that will serve as the base, it seems to protrude about 2mm.　

It would seem that 1mm on each side of the base would be just under the acceptable limit, but not very good looking.