Adafruit
Adafruit HDC3021 Precision Temperature & Humidity Sensor
· MPN: ADA5989
The Adafruit HDC3021 is a high-precision I²C temperature and humidity sensor breakout featuring the TI HDC302x series chip. With typical humidity accuracy of...
The Adafruit HDC3021 is a high-precision I²C temperature and humidity sensor breakout featuring the TI HDC302x series chip. With typical humidity accuracy of ±0.5% RH (and just 0.19% long-term drift) and temperature accuracy of ±0.1°C, it's one of the most accurate environmental sensors available at this price point.
The sensor operates across 1.8–5V power and logic levels with no external level shifters required, making it compatible with virtually any microcontroller or single-board computer. Four selectable I²C addresses allow multiple sensors on one bus for multi-zone monitoring. STEMMA QT / Qwiic connectors on the breakout enable solderless I²C connections.
Key Features
- ±0.5% Typical Humidity Accuracy – With 0.19% long-term drift for reliable readings over time
- ±0.1°C Typical Temperature Accuracy – High-precision environmental monitoring
- I²C Interface – Simple two-wire digital communication
- 4 Selectable I²C Addresses – Run multiple sensors on one bus
- 1.8–5V Compatible – No level shifters needed for any common microcontroller
- STEMMA QT / Qwiic Connectors – Solderless I²C connection
- Configurable Settings – Adjustable sensor rate, power mode, heater, alerts, and offsets
- NIST Tracking ID – Built-in traceability for calibration and compliance
- Arduino and CircuitPython Libraries – Full-featured driver support with example code
Ideal For
- High-precision environmental monitoring
- Indoor air quality and HVAC systems
- Multi-zone temperature and humidity tracking
- Scientific and industrial data logging
Package Contents
- 1× Adafruit HDC3021 Breakout Board – Fully assembled and tested with STEMMA QT connectors
- 1× Header strip (unsoldered)
Resources
Jargon buster
Plain-language definitions for the technical terms used above.
- breakout
- A breakout is a small circuit board that makes a tiny or hard-to-solder component easier to connect to with standard pins. It matters because this OLED module can be wired into a microcontroller project without needing to solder directly to the display’s fine contacts.
- CircuitPython
- A beginner-friendly version of Python designed to run directly on microcontroller boards. If a product supports CircuitPython, you can often program it by copying code files onto the board rather than setting up a more complex toolchain.
- microcontroller
- A microcontroller is a small computer on a chip that runs your program and controls connected inputs and outputs. For this product, it is the part that reads buttons and sensors, drives the display and speaker, and communicates over Bluetooth.
- Qwiic
- Qwiic is a plug-in connector system for I2C devices that uses small 4-pin cables, so you can connect compatible sensors without soldering. It matters because your controller or adapter also needs Qwiic, or you will need a cable or breakout to wire it up.
- single-board computer
- A complete computer built onto one circuit board, usually including the processor, memory, ports, and connectors. This matters because accessories like heatsinks must match the board’s layout and mounting holes to fit properly.
- STEMMA
- A plug-and-cable connection system used on some maker electronics boards to make wiring simpler. If a product uses STEMMA, you need the matching cable or connector type to plug it in without soldering.
- STEMMA QT
- A small plug-in connector system for I2C boards that lets you connect compatible sensors and controllers without soldering. It matters because it can make wiring faster and less error-prone, especially when adding several small modules to a project.
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