Although they are only as small as a pin head, they are changing everyday life in many fields: tiny Bosch micromechanical sensors. In fitness wristbands, they measure physical activity and help people achieve better health and well-being. In cars, sensors identify dangerous situations and instantly alert the control electronics to keep the vehicle on the road.
Because sensors detect the earth’s gravity, smartphones can change their screen orientation to suit users’ needs. Bosch is the world’s leading manufacturer of MEMS sensors (micro-electromechanical systems). Since the start of production in 1995, the company has manufactured more than six billion of them.
“The key challenge in the ongoing development of our MEMS sensors is their energy consumption. For example, more intelligence in sensors makes it possible for us to reduce energy consumption,” says Dr. Franz Lärmer, a Bosch sensor expert. It is hard to put a number on the many potential applications of sensors. They are a key technology for the internet of things (IoT).
Three approaches for lower energy consumption
Users of mobile devices such as smart watches, augmented-reality glasses, or wearables, often wish for longer battery runtimes, smaller designs, more affordable products, and more functions. Until now, the capacity of the batteries in such devices has often not been enough to keep the sensors and their analysis chips constantly supplied with power.
Devices have to be recharged more frequently if the sensor-supported functions are constantly in use. Moreover, better battery performance also opens the door to a wider range of intelligent applications. With the aim of reducing sensors’ energy consumption, Lärmer and his team in Renningen have joined forces with Bosch researchers in Palo Alto, California, to pursue three different approaches.
The first approach: energy can be harvested from changes in ambient pressure, vibration, or temperature. As part of the publicly funded joint project 9D-Sense, Bosch is working with partners to research this kind of energy harvesting. Tiny rechargeable batteries can store even the most minuscule amounts of energy gathered in this way to provide sensors with power over a long period of time, maintenance-free.
The second approach: sensors can be programmed to gather and transmit their data only when absolutely necessary. If a smartphone is lying still on a table, for example, its sensors do not need to be active.
The third approach: at its research center in Palo Alto, Bosch has developed the world’s smallest and most energy-efficient sensor unit. The contents of the BMI160’s tiny housing, which measures 2.5 x 3.0 x 0.8 millimeters, include an accelerometer and a yaw-rate sensor (gyroscope). In a smartphone, the sensor unit measures things such as position. It can also be found in tablet computers and smart watches.
In full operational mode, the BMI160’s typical power consumption amounts to a mere 950 microamperes, which is less than half the market standard, as well as a world record. This and other Bosch sensors can be found in three-quarters of all smartphones in the world today.
Every object capable of gathering information
“In the future, nearly all everyday objects are likely to be equipped with sensors. This is a revolutionary development that will allow almost every object to gather information about itself and its environment. As a result, the potential applications of these objects will increase tremendously,” Lärmer says.