HTU21D Humidity Sensor Hookup Guide
This Tutorial is Retired!
This tutorial covers concepts or technologies that are no longer current. It's still here for you to read and enjoy, but may not be as useful as our newest tutorials.
The HTU21D is a low-cost, easy to use, highly accurate, digital humidity sensor. All you need is two lines for I2C communication and you’ll have relative humidity readings such as “45.2%” or “23.1%” and very accurate temperature readings as a bonus!
Things you should know about this sensor:
- Uses the I2C interface
- Typical humidity accuracy of ±2%
- Typical temperature accuracy of ±0.3C
- Operates from 0 to 100% humidity but this sensor isn’t recommended for harsh environments where it could come in contact with water (such as rain).
- 3.3V sensor - use inline logic level converters or 10k resistors to limit 5V signals
- Here’s the datasheet
- Only one HTU21D sensor can reside on the I2C bus at a time
This sensor is ideal for environmental sensing and data logging. Perfect for a weather station or humidor control system. It is a very good replacement for digital humidity sensors such as the SHT15, SHT21, SHT25, HIH-4030, HIH6130 and capacitive humidity sensors such as the HH10D.
Things you might need to know:
- I2C Protocol
- Using the PCA9306 voltage translator
- Logic Levels
- Installing an Arduino library
- What are pull-up resistors?
- How to use a breadbaord