Capacitive Touch Sensor
https://docs.espressif.com/projects/esp-idf/en/stable/esp32/api-reference/peripherals/touch_pad.html
Video https://www.youtube.com/watch?v=JuV29EQ96uQ
Arduino IDE Tutorial https://randomnerdtutorials.com/esp32-touch-pins-arduino-ide/
Github example: https://github.com/espressif/esp-idf/tree/v5.2.3/examples/peripherals/touch_sensor/touch_sensor_v1/touch_pad_read