Wireless sensor harvests vibrations

Siemens has developed wireless sensors that use piezoelectrics and solar cells to draw energy from the environment in the form of light or vibrations.

The technology, which transmits its measured data by radio, is being marketed for conditioning monitoring in hard-to-acess areas.

This will enable industrial plants, for example, to be monitored more closely, revealing wear sooner and making it possible to avoid costly plant outages. Siemens claims that this will mean maintenance can be performed as needed, rather than at fixed intervals.

Head of Siemens’ wireless-sensor and RF technology research department, Leif Wiebking, said the sensors would be sensitive enough to detect when a single bearing within an electric drive in the plant needs replacing.

The sensor works, he explained, by sampling vibration signals from the drives and transmitting the information to a central receiver in the plant.

’If there is an unexpected signal in the vibration spectrum, there [could be] a bearing failure and you have to replace it and take the drive out of operation.’

Wiebking also said that a wireless, energy-autonomous sensor is less expensive and easier to install because it does not require integrating wires for signal transmissions or power supply. Also, he said, there is no need to replace batteries so a sensor can almost be installed and forgotten.

While Siemens is looking to commercialise the radio sensors for industrial plant monitoring, they could potentially be used for closed-loop control of building air-conditioning systems or monitoring overhead power lines in the future.