Automatic liquid level indication and control using passive UHF RFID tags

This paper proposes a new perspective to the liquid level monitoring and control technique by deploying energy efficient passive UHF RFID tags as liquid level sensors. The system consists of the pump, storage tank, level sensors (passive tags), RFID tag reader, pump control circuit, alarm circuit, and an indicator circuit. The tags are sealed (air and water tight), programmed with unique level labels using the Alien Reader software(860–868MHZ) and deployed to various levels of a storage tank for level monitoring and control. The mirrored P-shaped tag is designed modelled and deployed for use as the liquid level sensors. The RFID reader is disguised to form a part of the tank cover literarily few inches away from the tags. A variation of the tag readings received is used to infer level information which is communicated via the reader middleware to a computer database for monitoring.