a battery - free wireless sensor system enables high resolution and very accurate measurements of strain or other transducers with small signal outputs . the system may comprise a sensor tag , associated readers and data processing . the sensor tag may be based on passive rfid , or other passive devices that are powered by rf energy and that communicate with the powering source by backscatter , inductive coupling or reflected energy . the system may include a reader that powers the sensor tags with rf energy and that also wirelessly reads data from and writes data to the sensor tag . the reader software or host software may perform operations on the data that enable more accurate and useable information from the sensor tag . the invention may also include methods for data processes that improve the functionality and performance of the sensor system .