Sensors are the basis for the wide-ranging functionality of fitness trackers, smart watches and the like. Driven by growing demand from the wearables market, ever smaller, smarter and more energy-efficient systems are being developed.
According to PricewaterhouseCooper (PwC), the market for sensors in wearables is set to explode, reaching more than half a billion units by as early as 2019. “The Internet of Things – and especially wearable tech – is not only conquering industry, but also becoming an integral part of people’s everyday lives. That trend is escalating the demand for sensors,” comments Werner Ballhaus, Head of Technology, Media and Telecommunications at PwC. Motion sensors detect the movements of the body, while other sensors detect gravitational force and measure temperature or humidity for example. And there are lots of other sensors built into state-of-the-art wearables: in a recent report, Semico Research classified 11 different MEMS sensors and 12 conventional non-MEMS sensors. MEMS (Micro-Electro-Mechanical Systems) are tiny devices which combine logic modules and micro-mechanical structures in one chip. “Both MEMS and non-MEMS sensors are complementary in wearables and mobile devices,” said Tony Massimini, Semico’s Chief of Technology. “But there is also competition, as some MEMS sensors are likely to replace non-MEMS sensors.”
Cutting power consumption
The advantage of MEMS sensors: they are extremely small. “The key challenge in the ongoing development of our MEMS sensors is power consumption. We can reduce it by integrating more intelligence into the sensor, for example,” explains Dr Franz Lärmer, a sensor expert at Bosch. Intelligent programming makes sensors collect and transmit their data only when really necessary, meaning that while a smartphone is lying silently on the table, for example, its sensors can be turned off. The built-in intelligence also means that it is no longer necessary to switch an application processor or an additional discrete sensor hub out of standby to process the raw sensor data. That saves even more power.
Different data from one system
State-of-the-art sensor solutions combine multiple MEMS sensors in one unit, such as sensors to measure acceleration in different directions in conjunction with yaw rate sensors. That not only saves space, but also makes it easier to merge the data. Developers of new wearable devices can very easily integrate such complete systems into their designs, thereby significantly reducing the development cost.
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