RFID (radio frequency identification) tag system integrating sensing and identification
Technical Field
The invention relates to the technical field of RFID (radio frequency identification) tags, in particular to the technical field of an RFID tag system integrating perception and identification.
Background
RFID is a technology for achieving identification by direct contactless data communication between a reader and a tag. With the rapid development of the application of 5G, cloud computing, big data, sensors and other digital technologies, the method is a large-scale application of RFID, and meanwhile, RFID sensing tags with sensing capability are produced, and the method has wide application in the aspects of identity recognition, logistics, traffic, anti-counterfeiting, food and asset management and the like.
In general, when a reader and a tag are connected, the reader cannot directly acquire environmental data, such as environmental humidity and the like. In order to expand the data reading capability of the RFID, the reader can set or change the information related to the object stored on the tag like the conventional RFID, and can acquire the environment data.
Disclosure of Invention
The invention aims to: the invention provides an RFID label system integrating sensing and identification, which realizes two functions of reading information stored in a label and sensing environment by one RFID system.
In order to realize the purpose, the following technical scheme is adopted:
an RFID label system integrating sensing and identification comprises a sensor module, a reader and a label, wherein the label comprises a radio frequency front end module, a mode selector switch, an identification mode protocol state machine and a sensing mode protocol state machine; the mode change-over switch is a single-pole double-throw switch;
the input end of the radio frequency front-end module is in communication connection with a reader through a radio frequency signal, the output end of the radio frequency front-end module is connected to a common contact of a mode selector switch, a first contact of the mode selector switch is connected with an identification mode protocol state machine, a second contact of the mode selector switch is connected to a sensing mode protocol state machine, and the sensing mode protocol state machine is connected to the sensor module through a standard bus;
the identification mode protocol state machine provides a protocol for the identification mode, the perception mode protocol state machine provides a protocol for the perception mode, the reader sets or changes information which is stored on the tag and is related to a read object during the identification mode, and the reader obtains environmental parameters through the tag during the perception mode.
Preferably, the standard bus adopts an SPI bus.
Preferably, the rf front-end module includes an integrator, a discriminator, an inverter, and an SPI adaptation circuit, signals sent by the reader are input from inputs of the integrator and the inverter, an output of the integrator is connected to an input of the discriminator, an output of the discriminator is connected to an input of the SPI adaptation circuit, and the rf front-end module outputs a clock signal and a bus signal.
Preferably, the SPI adapter circuit includes a first resistor, a first capacitor, a second resistor, a third resistor, a second comparator, a first switch and a second switch, one end of the first resistor is used as an input end of the SPI adapter circuit, the other end of the first resistor is connected to an input end of the second comparator, an output end of the second comparator is used as an output end of the SPI adapter circuit, one ends of the second resistor, the first capacitor and the third resistor are all connected to a line between the first resistor and the second comparator, the other ends of the second resistor and the third resistor are respectively connected to one end of the first switch and one end of the second switch, and the other end of the first switch, the other end of the first capacitor and the other end of the second switch are grounded; the first switch is controlled by the clock signal and the second switch is controlled by the bus signal.
Preferably, in the identification mode, a gen-2 protocol is adopted to realize information exchange between the reader and the tag.
Preferably, in the sensing mode, the reader sends information to the tag through a Select instruction.
Preferably, the mode switch is controlled by a mode switching command issued by the reader.
The invention has the following beneficial effects:
the invention can realize two modes of the recognition mode and the perception mode by setting the recognition mode protocol state machine and the perception mode protocol state machine, and a single-pole double-throw switch is used for switching functions, and the two protocols do not work at the same time to prevent protocol conflict; the mode selector switch is directly controlled by the reader, so that the operation is more convenient and intelligent; the structural design of the radio frequency front-end module can well extract bus signals and clock signals; the sensing mode and the identification mode exchange information with the label through different information exchange modes, and the environmental sensing and the reading of the data stored in the label are realized.
Drawings
FIG. 1 is a schematic structural diagram of an integrated RFID tag system of embodiment 1 with sensing and identification functions;
fig. 2 is a schematic structural diagram of a radio frequency front end module according to embodiment 2;
fig. 3 is a schematic structural diagram of an SPI adaptation circuit according to embodiment 2.
Detailed Description
In order to make the objects, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are some, but not all, embodiments of the present invention. The components of embodiments of the present invention generally described and illustrated in the figures herein may be arranged and designed in a wide variety of different configurations.
Thus, the following detailed description of the embodiments of the present invention, presented in the figures, is not intended to limit the scope of the invention, as claimed, but is merely representative of selected embodiments of the invention. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
Example 1
In this embodiment, an RFID tag system integrating sensing and identification is shown in fig. 1, and includes a sensor module, a reader and a tag, where the tag includes a radio frequency front end module, a mode switch, an identification mode protocol state machine, and a sensing mode protocol state machine, where the mode switch, the identification mode protocol state machine, and the sensing mode protocol state machine form a protocol stack; the mode change-over switch is a single-pole double-throw switch;
the input end of the radio frequency front-end module is in communication connection with a reader through a radio frequency signal, the output end of the radio frequency front-end module is connected to a common contact of a mode selector switch, a first contact of the mode selector switch is connected with an identification mode protocol state machine, a second contact of the mode selector switch is connected to a sensing mode protocol state machine, and the sensing mode protocol state machine is connected to the sensor module through a standard bus;
the identification mode protocol state machine provides a protocol for the identification mode, the perception mode protocol state machine provides a protocol for the perception mode, the reader sets or changes information which is stored on the tag and is related to a read object during the identification mode, and the reader obtains environmental parameters through the tag during the perception mode.
Preferably, the standard bus is an SPI bus, and the mode switch is controlled by a mode switching command sent by the reader.
In the two modes, the tag and the reader have different data exchange modes to realize different functions with the assistance of different protocols.
In the embodiment, in a sensing mode, a reader sends information to a tag through a Select instruction, the tag is connected with a sensor module through a standard bus, and an RFID sends an instruction to the sensor module through the standard bus and acquires sensor data through the standard bus; the gen-2 protocol is used in the identification mode to acquire information, and the reader can realize data exchange with the tag through a Write/Read command.
When the label works, after the label obtains a mode switching instruction, the protocol state machine which works at present is closed, meanwhile, another protocol state machine is activated, after the label receives the mode switching instruction, the switch is switched to the other protocol state machine, and at any moment, the label has only one protocol state machine and is in an activated state.
Example 2
The scheme of this embodiment is based on embodiment 1, and is a preferred setting for a radio frequency front end module, as shown in fig. 2, the radio frequency front end module includes an integrator, a discriminator, an inverter, and an SPI adaptation circuit, signals sent by the reader are input from the inputs of the integrator and the inverter, the output of the integrator is connected to the input of the discriminator, the output of the discriminator is connected to the input of the SPI adaptation circuit, and the radio frequency front end module outputs a clock signal and a bus signal.
In this embodiment, referring to fig. 3, the SPI adapter circuit includes a first resistor, a first capacitor, a second resistor, a third resistor, a second comparator, a first switch and a second switch, one end of the first resistor is used as an input end of the SPI adapter circuit, the other end of the first resistor is connected to an input end of the second comparator, an output end of the second comparator is used as an output end of the SPI adapter circuit, one ends of the second resistor, the first capacitor and the third resistor are all connected to a line between the first resistor and the second comparator, the other ends of the second resistor and the third resistor are respectively connected to one end of the first switch and one end of the second switch, and the other end of the first switch, the other end of the first capacitor and the other end of the second switch are grounded; the first switch is controlled by the clock signal and the second switch is controlled by the bus signal.
The circuit uses an RC circuit to delay and compensate the data signal, and adjusts the signal to accord with the SPI protocol. When the signal input into the SPI adaptive circuit is '0', the output of the SPI adaptive circuit is also at low level; when the input is '1', the capacitor C starts to charge, the output bus signal is delayed for a period of time and then becomes high level, then when the data signal returns to low level, the clock signal comes to control the first switch K1, the second resistor R2 is connected into the circuit, the discharging speed of the RC circuit becomes slow, therefore, the output voltage of the capacitor can be higher than the threshold value of the first comparator when the clock signal exists, the bus signal can be kept to '1' when the clock signal exists, after the clock signal disappears, the second switch K2 is controlled to enable the first capacitor C1 to discharge and reset rapidly after the bus signal becomes low level, so that the next data can be processed.