The deformation monitoring of the structure is one of the most important topic of SHM. Beside the traditional wired sensing methods widely used in practical SHM applications, recently there are many attempts to develop wireless sensing solutions. The most attractive wireless sensing nodes are characterized by the lack of internal power source, draining energy from outside by utilizing different energy harvesting methods. This means that they could be determined as passive solutions. This paper presents completely new wireless method of deflection monitoring by using passive sensing platform based on RFID technology cooperating with CNT-based strain sensor, both developed by authors. Sensing node proposed in this paper consists of the wireless sensing platform and strain sensor connected to it. The sensing platform is based on the M24LR64E dual interface EEPROM from ST Microelectronics, being simultaneously the RFID chip and the low-power microcontroller MSP430F2132 from Texas Instruments. Both the platform and the sensor are powered via the alternating magnetic field developed by the standard HF RFID reader. The read range of such prepared sensing nodes are on the level of 40 cm and the powering range are on the level of 10 cm. The platform was connected to the CNT-based strain sensor that could be easily applied directly on the surface of the structure. Beside aforementioned features, the most important advantage is the possibility of placing sensing nodes in hard accessible places, for instance under some external layers of the structure. Thanks to the lack of internal power source, the platform could serve as a sensing node for many years without any maintenance active. Presented features of the wireless sensing platform prove its attractiveness for the structure deformation monitoring application related not only to the NDT or typical structure diagnostic activities, but primarily to SHM application characterized by special requirements. According to the best authors' knowledge, this is one of the first time in scientific literature when the completely passive wireless data collection from the CNT-based strain sensor is reported.
doi: 10.12783/SHM2015/130