AM2301 Capacitive Digital Temperature and Humidity Sensor

The AM2301 uses a capacitive humidity element rather than the resistive type found in cheaper sensors, which gives it meaningfully better long-term stability - a resistive humidity sensor tends to drift and needs periodic recalibration, while a capacitive element holds its accuracy for much longer under normal use. Both temperature and humidity are measured on the same die and output over a single digital wire, already calibrated at the factory, so no additional calibration step or lookup table is needed in the project's code.

Accuracy runs to ±3% relative humidity and 0.5°C temperature resolution in 0.1° steps - genuinely useful precision for anything beyond a rough estimate. Average current draw of just 300µA keeps it viable for battery-powered weather stations that need to run for months, and the single-wire digital interface means it only occupies one microcontroller pin regardless of which board it's connected to.

Common uses are outdoor and indoor weather station builds, greenhouse or terrarium climate monitoring, and HVAC or environmental data-logging projects wanting more long-term accuracy than a basic resistive humidity sensor provides.