Two Solutions of Soil Moisture Sensing with RFID for Landslide Monitoring

Abstract

Two solutions for UHF RFID tags for soil moisture sensing were designed and are described in this paper. In the first, two conventional tags (standard transponders) are employed: one, placed close to the soil surface, is the sensor tag, while the other, separated from the soil, is the reference for system calibration. By transmission power ramps, the tag’s turn-on power levels are measured and correlated with soil condition (dry or wet). In the second solution, the SL900A chip, which supports up to two external sensors and an internal temperature sensor, is used. An interdigital capacitive sensor was connected to the transponder chip and used for soil moisture measurement. In a novel design for an UHF RFID tag the sensor is placed below the soil surface, while the transponder and antenna are above the soil to improve communication. Both solutions are evaluated practically and results show the presence of water in soil can be remotely detected allowing for their application in landslide monitoring.

RFID over low cost VCSEL‐based MMF links: experimental demonstration and distortion study

“…Note that the focus of our experiments involves the achievable read range for the AMS tag. This is because this tag has sensor inputs which can be used in applications such as moisture monitoring [11]. The results for the Smartrack tag are reported mainly for comparison with the results obtained for the AMS tag.…”

Calibration of Passive UHF RFID Tags Using Neural Networks to Measure Soil Moisture

“…The idea proposed here, of using standard EPC/ GEN2 UHF RFID tags as soil moisture sensors, is described in a related work by Aroca et al [5], by Berkley and Sivandran [12], and by Pichorim et al [13]; however, these previous works do not provide calibration or reliable relation between some reference moisture sensor and RFID tag radio frequency (RF) properties. This section provides more details and a proposal for systematic experimental validation of the solution proposed in [5,12].…”

“…Between 2016 and 2018, some authors [5,12,13] have proposed the usage of standard passive UHF RFID tags as buriable soil moisture sensors, showing the feasibility of such approach; however, none of them present reliable calibration or correlation of real soil moisture content compared to RFID measurements. Berkley and Sivandran [12] even argue that such approach is viable, but the technology is still not mature for a reliable correlation between RFID tag properties and soil moisture.…”

Um Estudo das Reflexões de Sinais de RF em Sistemas RFID de UHF

“…Nos últimos anos tem-se percebido o aumento de tecnologias para monitoramento remoto aplicadas à agricultura, pecuária, ecologia e mesmo segurança urbana [1][2][3][4][5]. Assim, o uso de sistemas de comunicação pode trazer informações mais precisas das condições do solo, das encostas, das plantações, etc.…”

“…Dentre as opções de redes de sensores, o sistema de identificação por radiofrequência (RFID, radio-frequency identification) tem grande aplicabilidade na medição de parâmetros, como por exemplo, umidade em solo e temperatura [5]. Este sistema utiliza uma unidade remota de baixo consumo, ou mesmo passiva, chamada de tag (uma etiqueta eletrônica) e um sistema de excitação/leitura (reader ou leitor RFID).…”