Vibrations to help in energy harvesting

Sensors, transmitters, GPS modules need only a few milliwatts to operate, which could also be met by vibrations.

Berlin: Sensors, transmitters and GPS modules need only a few milliwatts of power to operate, which could also be met by vibrations produced by moving objects, thanks to a new technology - "energy harvesting".

But is this really enough to supply electronic microsystems? The answer lies in a compact data-logger installed on board, designed by the Fraunhofer Institute for Integrated Circuits, Germany.

This compact system analyses and characterises usable energy - in this case, the oscillations created during the ride. Data logger includes an acceleration sensor, a GPS module, a micro-controller, an SD card and a WiFi interface.

Experts refer to this underlying technology as "energy harvesting."

For instance, the vibrations generated by a high speed freight train could deliver enough energy to charge small electronic equipment: this is how the sensors that monitor temperatures in refrigerator cars, or GPS receivers, can receive the current they need to run, according to a Fraunhofer statement.

"We can use the data collected to design vibration converters, such as the piezoelectric generators, to feed the sensors, radio transmission receivers, tracking systems and other low-power-consuming devices with enough energy to power them," explains the Fraunhofer group manager and engineer Peter Spies.

"The tracking systems in use to date run on just a battery. These batteries need constant replacement, but that involves a lot of effort and expense. Thanks to energy harvesting, we can replace the batteries and wiring," adds Spies.

The energy "harvested" can be used for a great many other applications as well - to charge heart-rate monitors, sensors in washing machines and production plants, or measurement systems in cars to measure the air pressure in tires. The data logger is already in use in freight cars, trucks and machinery.

The researchers are showcasing a prototype of the data logger at the Sensor+Test 2012 trade fair, May 22-24 in Nuremberg, Germany.