An RFID tag with a moisture sensitive device, an RFID system and a humidity detection method

Abstract

The invention provides an RFID (Radio Frequency Identification Devices) label with a moisture sensor, an RFID system and a method for detecting moisture. Two pins are arranged on a chip of the RFID label; the moisture sensor and an antenna of the RFID label form a parallel-connection structure; a logic circuit for controlling on and off is arranged on a line, on which the moisture sensor and the chip of the RFID label are connected; the connected line and the logic circuit for controlling the on and the off are parts of the chip; when the logic circuit is off, the moisture sensor is not connected with the antenna in parallel, and is placed under the condition of a certain moisture, and after a time, a first resonant frequency and signal strength of the antenna are kept unchanged; when the logic circuit is on, the moisture sensor is connected with the antenna in parallel, and is placed under the condition of a certain moisture, and after a time, the antenna works under a second resonant frequency; and the RFID label receives a command sent from an RFID reader so as to control the on and the off of the logic circuit, so that the change of the moisture can be detected through comparing difference between signal strengths of different frequencies of the antenna. According to the invention, the change of the moisture can be detected with lower cost.

Description

technical field [0001] The present invention relates to the technical field of RFID (Radio Frequency Identification, radio frequency identification), in particular to an RFID label with a humidity sensitive device, an RFID system and a humidity detection method. Background technique [0002] In recent years, RFID systems have become increasingly common. RFID systems are mainly used for the identification of people and objects. Generally speaking, the system includes at least one RFID reader, which can transmit and receive radio frequency signals from one or more RFID tags within a set range. The RFID tag is usually encapsulated and can be attached to an object, and it includes a microchip that communicates with the antenna. The microchip is generally an integrated circuit that stores and processes information, modulates and demodulates radio frequency signals, and performs other specialized functions. An RFID tag's antenna is used to receive and transmit radio frequency s...

AI Technical Summary

Problems solved by technology

Generally these devices require a continuous power source for the sensing device to detect changes in humidity, but this adds to the cost of the device

In addition, some devices require the sensing device to be connected to a comparator circuit to detect the degree of deviation from the reference voltage, which greatly increases the cost of the device

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