Sensirion sensor SHT40 is the first type of the 4th generation of humidity and temperature sensors for mobile and battery-driven applications. It builds on a completely new and optimized CMOSens® chip offering reduced current consumption and improved accuracy.
Reduced Power Consumption
When we compare the most accurate modes of SHTC3 (normal mode, repeatability 0.1% RH) and SHT40 (high repeatability mode, 0,08% RH), sensor SHT40 consumes only 2.3uA, which is 53% less than SHTC3. When both sensors run in the lowest power mode, SHT40 sensor consumes 20% less than SHTC3.
Extended Power Supply Voltage Range
SHT40 has input voltage range 1.08 to 3.6V, allowing to utilize the full capacity of 3V Li primary battery. In addition, several types of microcontrollers that can operate with a supply voltage from 0.9 V are already available on the market. This allows powering a device from a cheap 1,5V alkaline battery.
Sensor SHT40 is available as SHT40-AD1B with I2C address 0x44 and SHT40-BD1B with I2C address 0x45. Therefore, it is possible to use two SHT40 sensors on the same I2C bus.
Full Water Condensation Robustness
If water condenses on the sensor surface, SHT40 will measure RH=100%. This seems natural, but for some competing sensors, water condensation will cause that the RH measured by the sensor drops to 0%.
The sensor incorporates an integrated variable power heater which can be switched on by sending a command through I2C. The heater can remove condensed water from the sensor surface and also prevent measurement error caused by long-term operation in a high humidity environment, e.g. +3% RH after 60 hours at RH > 80%
How to Start with SHT40
If you need more information about Sensirion products, please contact your SOS sales representative for your region or do not hesitate to contact us at firstname.lastname@example.org, we will be happy to help.
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