A novel wireless sensor for use on bridges that is powered by the vibrations of vehicles passing overhead has been developed by researchers at Clarkson University in Potsdam, USA. The device, which measures temperature, humidity, light and pressure, could function for years without requiring maintenance or battery replacement.

The sensor is composed of an electromagnetic energy harvester and energy conversion circuitry that are made up of piezoelectronics and supermagnets that could be produced from a range of materials, explains Assistant Professor Edward Sazonov.

When the harvester is excited by vibrations, it produces AC voltage on the output, which is conditioned into low-voltage DC and stored. Once enough energy has been collected, the sensor powers up, takes a measurement, and transmits the data over a wireless link.

‘Traffic excitation is not steady but rather generates pulses of energy,’ says Sazonov. ‘The electronics track the optimal point of energy conversion and efficiently harvest those pulses.’

The team has successfully completed a field test, and is looking to conduct longer-term trials, as well as improve the amount of energy produced by the system.