RFID (radio frequency identification) is a kind of typical IOT technology. It uniquely identify an object by radio frequency without mechanical or optical contact. Compared to the barcode identification, RFID is far more automated,efficient & accurate. An RFID system consists of a reader (antenna + transceiver) & a tag.The reader uses radio frequency waves to transmit a signal that activates the tag. When activated, the tag transmits data back to the reader. The data is used to notify a programmable logic controller that an action should occur.