ESP32 C3 supermini

 In order for the ESP32 supermini to send data back, need to set the USB CDC on Boot to 'Enable'

 

reference: 

ESP32 interrupt

 https://lastminuteengineers.com/handling-esp32-gpio-interrupts-tutorial/

https://techtutorialsx.com/2017/10/07/esp32-arduino-timer-interrupts/

Watchdog timer

https://docs.espressif.com/projects/arduino-esp32/en/latest/api/timer.html

PID motion

https://www.dfrobot.com/blog-1045.html

ESP32 with HR-oximeter max20102

 https://microcontrollerslab.com/esp32-heart-rate-pulse-oximeter-max30102/