The GY-21 HTU21 Temperature and Humidity Sensor Module is a low cost, easy to use, high accuracy digital humidity, and temperature sensor. This sensor is ideal for environmental sensing and data logging and perfect for weather stations or humidor control systems. All you need is two lines for I2C communication and you’ll have relative humidity and very accurate temperature readings as a bonus!

There are only four pins that need to be connected to start using this sensor in a project. One for VCC, one for GND, and two data lines for I2C communication. This breakout board has built-in 4.7k pull-up resistors for I2C communication. If you’re connecting multiply I2C devices on the same bus, you may want to turn off these resistors.

Features:

2.1V to 3.6V Supply Voltage
Low power consumption – 0.15uA typical
I2C interface
Resolution: 0.04%RH, 0.02°C
Accuracy: ±2%RH, ±3°C

Specifications:

Interface	I2C
Operating Voltage (VDC)	2.1 ~ 3.6
Current Consumption	0.15uA
Resolution	0.04%RH, 0.02°C
Accuracy	±2%RH, ±3°C
Length (mm)	21
Width (mm)	16
Weight (gm)	1.02