Sensirion SHT31 Smart Gadget – an ‘out of the box’ experience

The Sensirion SHT31 (123-7130) Smart Gadget is a temperature and humidity sensor device providing a fast and easy route for getting set up and communicating remotely via Bluetooth.

Having acquired one of these little beauties, I was keen to see exactly what the compact box could contain. This series of sensors is becoming more widely used and is appearing in many products, including automotive, HVAC and consumer products where accurate temperature and humidity measurement is essential. 

The bright green box is compact at just 8 cm x 3.5 cm x 0.8cm and upon opening, you’ll find the sensor board, instruction sheet, plus a neat PCB stand which cleanly snaps in two and clips onto the module allowing it to stand on a table top. The CR2032 battery (866-0672) is already installed in an on-board battery holder so all that is required is to pull the insulating tab out of the holder and the display springs into life.

The display shows both temperature and % relative humidity on the LCD display with a resolution of 0.01 and an update rate of about 1 second.

The upper display shows % relative humidity and by briefly pressing the switch, this changes to the dew point value in degrees Celsius. Degrees Fahrenheit can also be set as an alternative by pressing the switch as the battery is inserted.

 The major feature is the Bluetooth SMART mode which is activated by pressing the button for over 1 second. The display momentarily shows RFON and the Bluetooth icon starts flashing with the Smart Gadget ID temporarily shown on the display also. It is now visible to master devices on Bluetooth.  

The Smart Gadget app is available for Android and iOS devices. Having preloaded this onto my smartphone, upon opening the app I was ready to connect. Selecting ‘Settings’ then clicking on the ‘Smart Gadgets’ tab starts the search, with my gadget quickly becoming available and showing as connected in the Settings Connections screen. 

The app is great and allows remote monitoring. With it I managed to achieve a range of up to 20m in the office environment. 

The Dashboard will show the temperature, humidity, dew point and heat index actual values.

The ‘Comfort Zone’ tab shows a graphical display which plots the temperature and humidity and shows this as the overall comfort level being experienced.

Historical data is available in the ‘History’ tab where graphs showing temperature, humidity, dew point and heat index can be displayed by selecting the graph title at the top of the screen and choosing the required data. The settings screen allows the data logging details to be changed by tapping the smart gadgets bar, then the current connected device name (or required device name if multiple devices are connected). The logging interval can be changed from 1 second to 3 hours and data download can be actioned.

 All this functionality is available straight out of the box, so it is certainly worth exploring the Sensirion SHT31 (123-7130) Smart Gadget in more detail and considering using it in a future design. 

SHT31 Smart Gadget Development Module RS (123-7130)

SHT31-DIS-B Series Temperature & Humidity Sensor RS (876-5061)

SHT31-ARP-B Analogue Output Temperature & Humidity Sensor RS (876-5067)