An RFID reader with onboard sensing capability for monitoring fruit quality

We report on the development of an RFID reader with onboard micro-machined metal oxide gas sensors aimed at monitoring climacteric fruit during transport and vending. The developed platform integrates a commercial off the shelf inductive coupling RF transceiver in the 13.56 MHz band, fully compliant with the ISO15693 standard, micro-hotplate gas sensors, driving and readout electronics. By operating the sensors at a fixed temperature, we show that the reader could work as an alarm level monitor able to assess the conservation stage of apples. Furthermore, if the sensors are operated under an optimised temperature-modulation mode, we show that accurate calibration models for the species that are relevant to assess the conservation stage of apples (i.e., ethylene, acetaldehyde and ethanol) can be built.