This library provides a quick and easy way to set up an ADC on AVR
microcontrollers and retrieve the values in 8-bit or 10-bit format in an
interrupt driven fashion.
Nowadays even the cheapest microcontroller has a build-in ADC (Analog to Digital Converter). An ADC converts analog signals into digital signals and can be used in a wide range of applications like recording a signal from a microphone into a digital format, reading light sensors like an LDR (light dependent resistor), measuring current consumption, reading temperature or humidity sensors, etc. All these requires voltage measurements that an ADC can do.