Development of a laser-powered wireless strain gauge device using a continuous-wave laser and photovoltaic cell

Wireless sensors have emerged as a reliable method for structural health monitoring. Wireless sensors should ideally have their own power supply, which is a conventional battery in most cases. However, sensors are often retrieved, and batteries must be replaced because of their finite lifespan. In many applications, wireless sensors must be operated in locations that are difficult to access, and these systems often have a desired operational lifespan that exceeds that of conventional batteries. Given this limitation, research devoted to alternative methods, such as energy harvesting or wireless power transmission of batteries, has rapidly increased. In this article, we investigated potential solutions to this challenge by collecting energy from a laser beam to power a wireless sensor. The proposed laser power transmission system features the capabilities of transmitting power to and rapid switching direction to sensor nodes using a laser mirror positioner. The delivered light is captured by a photovoltaic cell and collected in a storage medium to supply the required power to a wireless strain gauge device. Validation of the proposed technology was performed by static and dynamic strain measurements, and the obtained signals from the wireless strain gauge device were compared with those of the wired data acquisition.