The moisture of the human skin plays an important role in two other applications as well. Motorcycle drivers and skiers as well as users of VR glasses often suffer from a problem: due to moisture – caused by perspiration – the visor of a helmet, ski glasses or even the lenses of VR glasses can fog up.
An application from the automotive sector shows how this problem can be solved: every year, millions of humidity sensors from Sensirion, which meet the quality standards of the automotive industry - and are, thus, larger as well as more expensive - are used for detecting condensation on the windscreen of vehicles. The humidity and temperature sensor determines the dew point and controls the air conditioning or ventilation as necessary.
Thanks to the low power consumption, the microscopically small size, as well as the cost effectiveness of the SHTW2 humidity sensor, such functions can now also be realized in more price-sensitive applications in the consumer electronics sector.
The direct measurement of perspiration on the skin is another possible application of the SHTW2 in the wearables sector. The water that a human body loses through perspiration must be replaced to prevent dehydration. Elderly people, in particular, can quickly be at risk if the fluid balance is not maintained.
Direct determination of the perspiration can easily be realized with the SHTW2 by means of a device that is worn on the wrist. Here, two of the humidity and temperature sensors are mounted in a channel of sorts, one end of which is in contact with the skin. The perspiration rate can thereby be precisely determined using diffusion equations. The device can then remind the wearer to drink adequate fluids as necessary.
Development platforms and example applications
Sensirion supports developers in making the implementation and testing of their applications as simple as possible. Evaluation kits are available for all of Sensirion’s humidity sensors for quick and easy initial measurements.
Specifically for the SHTW2 humidity sensor, the sensor expert offers a so-called Xplained Pro Dual Humidity and Temperature Extension Board that is equipped with two SHTW2 humidity sensors and is compatible with the Xplained Pro Platform from Atmel. For the development of mobile communication applications, the SHTW2 is also available on a Qualcomm DragonBoard.
Not only does Sensirion make available the appropriate boards with sensors for various platforms, the company also supplies example source codes on the “developer.sensirion.com” developer website that developers can use to immediately start their own projects. In general, the developer website offers a platform for the maker community in which possible uses of environmental and flow sensors are presented to serve as a source of inspiration for the realization of one’s own projects.
With the new SHTW2, a high-performance humidity and temperature sensor is available in a chip-scale package. It can be used to implement even price-sensitive applications, e.g., for wearables, though many new possibilities will open. Sensirion supports the developers of such applications both with corresponding development kits as well as with example applications for which the source code is freely available.
About the author:
Herr Vincent Hess is Senior Product Manager for Humidity Sensors at Sensirion AG - www.sensirion.com