We stock a large number of Temperature/Humidity sensors, so you’re probably wondering why another one? Well, this Adafruit HDC3022 Precision Temperature & Humidity Sensor breakout features the highest accuracy & precision we’ve seen so far! It has theTI HDC302x series chip with typical 0.5% accuracy for the RH sensor (with 0.19% long-term drift) and 0.1C typical accuracy for the temperature sensor. All at a very nice price.

This sensor has a true I2C interface for easy interfacing with only two wires (plus power and ground!). That makes it preferable to the janky DHT11/DHT22 sensors. The sensor is 5V safe, so you can use 1.8V to 5V power and logic levels without the need for shifters, so you can power and communicate with it using any microcontroller or microcomputer. With 4 selectable I2C addresses, you can have multiple sensors on one bus – unlike many other fixed-address T/RH sensors.

We’ve written a full-featured Arduino and CircuitPython/Python library, so whether you have an 8-bit microcontroller or a quad-core Raspberry Pi, you will be able to quickly get data from the sensor for your environmental monitoring needs. The library can set up the sensor rate/power, heater, alerts, offsets, and read data or NIST tracking ID.

Such a lovely chip – so we spun up a breakout board with the HDC3022 and some supporting circuitry such as pullup resistors and capacitors. To make things even easier, we’ve included SparkFun Qwiic compatible STEMMA QT connectors for the I2C bus so you don’t even need to solder! QT Cable is NOT included, but we have a variety in the shop.

If you prefer working on a breadboard, each order comes with one fully assembled and tested PCB breakout and a small piece of header. You’ll need to solder the header onto the PCB, but it’s fairly easy and takes only a few minutes even for a beginner.

Please note: this sensor comes with a protective polyamide sticker on top, please remove it before usage!

Revision History

• As of October 31st, 2024 We’ve upgraded this sensor to now be the “HDC3022” rather than the “HDC3021”. It is completely the same other than it now has a white PTFE filter cover that should not be removed and will keep your sensor nice and clean

Specifications

HDC302x specifications:

• Relative humidity (RH) sensor:
  Operating range: 0% to 100%
  Accuracy: 0.5% typical
  Offset Error Correction: reduces offset to return the device to within accuracy specification
  Long-term drift: 0.19%RH/yr
  Condensation protection with integrated heater
• Temperature sensor:
  Operating range: 40C to 125C
  Accuracy: 0.1C typical
• NIST traceability: relative humidity & temperature
• Low power: average current 0.4 A (sensor only, not including on-board green LED which can be disabled)
• I2C interface compatibility up to 1-MHz speeds
  Four selectable I2C addresses
  Data protection through CRC checksum
• Supply voltage: 1.62 V to 5.50 V
• Available auto measurement mode
• Programmable interrupts
• Programmable RH and Temp measurement offset
• Dimensions: 25.4mm x 17.7mm x 4.7mm
• Weight: 1.6g