This project is a great example. [Scott Daniels] takes a look at the other voltage measurement options available to AVR chips used by Arduino.

The EasyNixie Arduino compatible low-voltage Nixie Tube driver module has emerged as a versatile and user-friendly tool for hobbyists and professionals alike. This module, designed with a focus on ...

2.7V - 5.5V operating voltage (Arduino mode) 1.8V - 5.5V operating voltage (with custom fw) 20 I/Os (14 Digital, 6 Analog / Digital I/O) - All the signals on the Arduino Shield connectors are ...