GY-21-HTU21 Humidity & Temperature Sensor

Can be placed in soil to measure moisture and temperature, which makes it ideal for use in a garden or greenhouse. The humidity sensor is also especially useful in building remote weather stations.


12 in stock

Add to Wishlist
GY-21-HTU21 Humidity & Temperature Sensor
This item: GY-21-HTU21 Humidity & Temperature Sensor

12 in stock

LM35DZ DC 4-30V Digital LM35 Temperature Sensor Linear Analogue Output Sensor
BME280 3.3v I2C or SPI Temperature Humidity Pressure
GY-271 HMC5883L Electronic Compass Triple Axis Magnetometer Sensor
Qty Discount
2 - 4 5%
5 - 9 6.5%
10 + 8%
SKU: TS-P738
Additional information
Support & Utility
Q & A

GY-21-HTU21 Humidity & Temperature Sensor is a low-cost, easy-to-use, highly accurate digital humidity and temperature sensor.

This sensor is ideal for environmental sensing and data logging and perfect for weather stations for humidity control systems. All you need is two lines for I2C communication, and you’ll have relative humidity readings and very accurate temperature readings as a bonus!


  • 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
  • Size: 21mm x 16mm 

Package included:1x GY-21-HTU21 Humidity & Temperature Sensor

Check out our On Sale and Clearance Items 

Development  Resources: Demo Codes, Schematics, Datasheets, Etc


Tempero systems Hackaday     Hackaday serves up Fresh Hacks Every Day from around the Internet.

tempero systems-InstructablesInstructables is a community for people who like to make things. Explore, share, and do your next project with us!

Tempero Systems-Github     Where the world builds software

tempero systems-Raspberry Pi    Raspberry Pi Foundation What would you like to make today?

tempero systems-Arduino    Arduino‘s mission is to enable anyone to enhance their lives through accessible electronics and digital technologies.

tempero systems-Wikipedia
Wikipedia is a free online encyclopedia created and edited by volunteers worldwide and hosted by the Wikimedia Foundation.



1. There may be slight size deviations due to manual measurement, different measuring methods and tools.
2. The picture may not reflect the actual colour of the item because of different photographing lights, angles and display monitors.


Weight 0.0010 kg
Dimensions 2.2 × 1.7 × .5 cm

Product Applications

  • The Humidity and Temperature Sensor is an Arduino-compatible sensor board that carries an SHT21 digital humidity and temperature sensor from Sensirion. It has a 4-pin interface that can communicate directly with the analogue pins on the Arduino.
  • The SHT21 utilizes a capacitive sensor element to measure humidity, while the temperature is measured by a band-gap sensor. Both sensors are seamlessly coupled to a 14-bit ADC, which then transmits digital data to the Arduino over the I2C protocol. Because of the sensor’s tiny size, it has incredibly low power consumption, making it suited for virtually any application.
  • To optimize the accuracy of temperature and humidity readings, the SHT21 sensor is placed at the tip of the board, isolating it from heat-producing circuitry. Two of the sensor’s four pins are ground and +5V; the other two are clock and data pins that make up the 2-wire serial interface. The board is 5V tolerant and designed to operate directly off the supply voltage coming from the Arduino.

Current Product Support

SKU Product Type Download/View
TS-P738 GY-21-HTU21 Humidity & Temperature Sensor - HTU21 Datasheet Download

Q & A

There are no questions yet

Ask a question

Your question will be answered by a store representative or other customers.

Thank you for the question!

Your question has been received and will be answered soon. Please do not submit the same question again.



An error occurred when saving your question. Please report it to the website administrator. Additional information:

Add an answer

Thank you for the answer!

Your answer has been received and will be published soon. Please do not submit the same answer again.



An error occurred when saving your answer. Please report it to the website administrator. Additional information: