Adafruit HTS221 - Temperature & Humidity Sensor Breakout Board

Humidity is the concentration of water vapor in the air, and it can significantly affect everything from your comfort to the longevity of sensitive electronics. Places with high humidity can feel like saunas, causing discomfort, while low humidity environments may lead to nosebleeds and static electricity.

The HTS221 Temperature and Humidity Sensor by ST is designed to accurately measure relative humidity from 0% to 100% with a sensitivity of 0.004% and 3.5% accuracy between 20%-80%. It also measures temperature ranging from -40 to 120 degrees C, with a resolution of 0.016°C and ±0.5 °C accuracy between 15 and +40 °C.

This sensor is particularly useful for applications such as monitoring the humidity in a bathroom or a mushroom farm. It supports both 3-wire SPI and I2C communication, the latter of which is simplified with SparkFun Qwiic compatible STEMMA QT connectors. The HTS221 is mounted on a breakout board with level shifting and a power regulator, making it compatible with 5V logic level devices like Metro 328 or Arduino Uno, and 3.3V logic level devices like Feather M4 or Raspberry Pi.

The sensor comes with libraries for Arduino and CircuitPython or Python, alongside example code and instructions, so you can start measuring in minutes. Its small, 2mm square size ensures that it fits neatly into a variety of projects.