ADS1115 16-Bit I2C ADC 4-Channel Module

A microcontroller's built-in ADC is usually 10 or 12-bit, which is fine until a project needs to resolve a small signal change precisely - a load cell, a precision temperature sensor, a photodiode reading fine light changes. The ADS1115 adds a 16-bit external ADC over I2C, four times the resolution of a typical Arduino's onboard converter, with a programmable gain amplifier that can boost a small differential signal up to 16x before conversion.

Four channels can be read as four single-ended inputs or as two differential pairs, and up to four boards can share one I2C bus simultaneously thanks to address-selection jumpers, useful when a project needs more analog channels than any single board provides. Power draw is low enough for battery projects, with an auto shutdown single-shot mode for further savings.

Common uses are precision sensor readings that a built-in ADC cannot resolve finely enough, differential signal measurement, and any project already out of onboard analog pins.