SHT3x – Temperature and Humidity Sensor

In this blog we look at the Sensirion SHT3x Temperature/Humidity sensors are some of the finest & highest-accuracy devices you can get. And, finally we have some that have a true I2C interface for easy reading. The SHT30 sensor has an excellent ±2% relative humidity and ±0.3°C accuracy for most uses. Unlike earlier SHT sensors, this sensor has a true I2C interface, with two address options. It also is 3V or 5V compliant, so you can power and communicate with it using any microcontroller or microcomputer.

 

SHT3X

The digital SHT3x humidity sensor series takes sensor technology to a new level. As the successor of the SHT2x series it sets the industry standard in humidity sensing. The SHT3x humidity sensor series consists of a low-cost version with the SHT30 humidity sensor, a standard version with the SHT31 humidity sensor, and a high-end version with the SHT35 humidity sensor. Automotive grade versions are also available. The SHT3x humidity sensor series combines multiple functions and various interfaces (I2C, analog voltage output) with a applications-friendly, very wide operating voltage range (2.15 to 5.5 V). The SHT3x humidity sensor is available in both large and small volumes.

SHT3X board Pinouts

The HTU21D-F is a I2C sensor. That means it uses the two I2C data/clock wires available on most microcontrollers, and can share those pins with other sensors as long as they don’t have an address collision.

Changing the default I2C address

ADDR/AD0 Jumper – I2C Address pin. Pulling this pin high or bridging the solder jumper on the back will change the I2C address from 0x44 to 0x45

Breakout scheme

The basic concept of a breakout board is that is takes a single electrical component and makes it easy to use. Usually the electrical component is an integrated circuit (IC). Integrated circuits, as you may know, have pins on them. The pins on an IC can do a multitude of things, but you usually have pins for supply power, pins for providing a ground, pins for receiving an input and pins for sending an output. A breakout board “breaks out” these pins onto a printed circuit board that has its own pins that are spaced perfectly for a solderless breadboard, giving you easy access to use the integrated circuit.

Interfacing SHT3X with Arduino using I2C Interface

The sht3X light intensity sensor has a I2C Interface. We will have a look how to use the I2C Pins of sht3X to interface it with Arduino Nano Board. The connection between sht3X & Arduino Nano is fairly simple. Connect the VCC pin of the sht3X to Arduino 3.3V Pin and GND to GND. Similarly, connect the I2C Pins of sht3X, SDA and SCL Pins to Arduino A4 and A5 Pins respectively.

SHT3X Library’s

The sht3X Library developed by Rob Tillaart can measure the temperature & humidity. The library is simplified and using only few lines of code, you can interface SHT3X with the Arduino Nano. To begin reading sensor data, you will need to download the Adafruit SHT31 library from the Arduino library manager.

Download: SHT31

Or download the  SHT31 library trough the Arduino library manager.

Source Code/program

Testing & Results

You can use the above circuits, the I2C circuit. Then upload one of the codes according to the circuit diagram. Open the serial monitor after uploading the code to the Arduino Nano board.

The serial monitor displays the temperature in degrees Celsius and Humidity in percentages.
 

REFERENCE

Sensirion AG Switzerland,Digital Humidity Sensor SHT3x (RH/T)(2021), The digital SHT3x humidity sensor series takes sensor technology to a new level. , https://www.sensirion.com/en/environmental-sensors/humidity-sensors/digital-humidity-sensors-for-various-applications Sensirion AG Switzerland,Datasheet SHT3x-DIS(2021), SHT3x-DIS is the next generation of Sensirion’s temperature and humidity sensors, https://www.sensirion.com/fileadmin/user_upload/customers/sensirion/Dokumente/2_Humidity_Sensors/Datasheets/Sensirion_Humidity_Sensors_SHT3x_Datasheet_digital.pdf  Adafruit, Adafruit Sensirion SHT31-D – Temperature & Humidity Sensor (2021),Adafruit SHT31-D Library, https://github.com/adafruit/Adafruit_SHT31