CN202694365U

CN202694365U - Radio frequency identification card reader for library management system

Info

Publication number: CN202694365U
Application number: CN 201220400130
Authority: CN
Inventors: 魏晓慧
Original assignee: Huizhou University
Current assignee: Huizhou University
Priority date: 2012-08-14
Filing date: 2012-08-14
Publication date: 2013-01-23
Anticipated expiration: 2022-08-14

Abstract

The utility model discloses a radio frequency identification RFID card reader for a library management system. The RFID card reader comprises a master control module, a radio frequency read-write module and an antenna module, wherein the master control module comprises a master control single-chip microcomputer, and a parallel control interface, a serial communication interface, a crystal oscillator circuit, a power supply circuit and an expansion interface which are connected with the master control single-chip microcomputer, the radio frequency read-write module comprises a radio frequency read-write chip connected with the parallel control interface and a high-frequency filter circuit connected with the radio frequency read-write chip, and the antenna module comprises a coupling circuit connected with the high-frequency filter circuit and an antenna coil connected with the coupling circuit. The RFID carder reader can be applied to large library management systems or company supply-chain production management systems, work in various severe environments, identify objects moving at a high speed, simultaneously identify multiple labels, and intelligently identify, locate, track, monitor and manage the library management system; and operation of the RFID card reader is convenient and fast.

Description

A kind of radio frequency identification card reader for library management system

Technical field

The utility model relates to card reader, particularly a kind of radio frequency identification card reader for library management system.

Background technology

As everyone knows, need a kind of general storage medium to carry out exchanges data between the various products such as computer, digital product, household electrical appliances, mention card reader, a lot of people can expect immediately that this product is to cooperate digital camera and produce, but card reader no longer has been confined to digital camera and has used at present, but have expanded to more field, such as gate control system, food security is traced to the source etc., and everything all will give the credit to the appearance of Internet of Things.

Internet of Things, a kind of by information sensing equipment such as radio-frequency (RF) identification (RFID), infrared inductor, GPS, laser scanners, agreement by agreement, any article are connected with the internet, carry out message exchange and communicate by letter, to realize a kind of network to intellectuality identification, location, tracking, monitoring and the management of article.Library management system is an Internet of Things just, but current library management system ubiquity function is simple, the shortcoming of complicated operation, inconvenience.Most library management system all can not carry out long distance wireless operation, and this has affected user's experience to a certain extent, also so that operating efficiency can not improve.

Summary of the invention

In order to overcome the shortcoming and defect of prior art, the utility model provides a kind of radio frequency identification card reader for library management system.

The purpose of this utility model realizes by following proposal:

A kind of radio frequency identification card reader for library management system comprises main control module, radio frequency module for reading and writing and Anneta module.Described main control module comprises main control singlechip and the parallel control interface, the serial communication that link to each other with main control singlechip get final product, crystal oscillating circuit, power circuit and expansion interface.The radio frequency module for reading and writing comprises the radio frequency read-write chip that links to each other with the parallel control interface and the high-frequency filter circuit that links to each other with the radio frequency read-write chip.Anneta module comprises the match circuit that links to each other with high-frequency filter circuit and the aerial coil that links to each other with match circuit.

Described main control singlechip is connected circuit to be connected with the radio frequency read-write chip by the parallel control interface by data line, address wire and control line, and the normal operation of control radio frequency read-write chip realizes and the communicating by letter of rfid card thus.

Described main control singlechip has adopted single-chip microcomputer STC89C52, comprise 8k bytes Flash storer, 256 byte RAM storeies, 32 I/O mouth lines, WatchDog Timer, 2 data pointers, three 16 bit timing device/counters, 2 grades of interrupt structures of one 6 vector, crystal oscillator and clock circuit in the full duplex serial port sheet.

Described radio frequency read-write chip is responsible for receiving the control information of main control singlechip and is finished traffic operation with rfid card.

Described radio frequency read-write chip adopts MFRC500, and there are 64 registers inside, and uses independently reading and writing signal wire parallel interface and the multiplexing mode of data/address wire to be connected with single-chip microcomputer STC89C52.

The utlity model has following advantage and effect:

(1) the identification work of card reader need not manual intervention, can work in various rugged surroundings, also can identify high-speed moving object simultaneously and can identify simultaneously a plurality of labels, and is swift and convenient to operate;

(2) can intelligent identification, location, follow the tracks of, monitoring and management library management system, can carry out the long distance wireless operation by antenna part, improve the user's that knows clearly experience and operating efficiency;

The utility model is applicable in the supply chain production management system of large-scale library management system or company.

Description of drawings

Fig. 1 is the hardware system composition frame chart of the utility model one embodiment.

Fig. 2 is the connecting circuit figure of single-chip microcomputer STC89C52 and the radio frequency read-write chip MFRC500 of Fig. 1.

Fig. 3 is the high-frequency filter circuit of Fig. 1 and the circuit diagram of match circuit.

Embodiment

Below in conjunction with embodiment and accompanying drawing the utility model is described in further detail, but embodiment of the present utility model is not limited to this.

Shown in Fig. 1 hardware system composition frame chart of the present utility model, a kind of radio frequency identification card reader for library management system mainly comprises main control module, radio frequency module for reading and writing and Anneta module.In the present embodiment, main control module comprises main control singlechip and the parallel control interface, the serial communication that link to each other with main control singlechip get final product, crystal oscillating circuit, power circuit and expansion interface.The radio frequency module for reading and writing comprises the radio frequency read-write chip that links to each other with the parallel control interface and the high-frequency filter circuit that links to each other with the radio frequency read-write chip.Anneta module comprises the match circuit that links to each other with high-frequency filter circuit and the aerial coil 1 that links to each other with match circuit.

Main control singlechip is connected circuit to be connected with the radio frequency read-write chip by the parallel control interface by data line, address wire and control line, and the normal operation of control radio frequency read-write chip realizes and the communicating by letter of rfid card thus.Main control singlechip can communicate by serial communication interface and computing machine (PC) in addition, thereby realizes the information transmission of PC and radio-frequency card.In the present embodiment, main control singlechip adopts the STC89C52 single-chip microcomputer that has the program storage of 8K and have serial-port able to programme, two 16 bit timing device/counters, 5 interrupt sources.

The radio frequency read-write chip is responsible for receiving the control information of main control singlechip and is finished traffic operation with rfid card.In order to work, the radio frequency read-write chip must select suitable parallel interface to be connected with main control singlechip, and in order to send, receive stable high-frequency signal, the radio frequency read-write chip will be connected with Anneta module by high-frequency filter circuit.In the present embodiment, cost performance is the highest in the radio frequency read-write chip of radio frequency read-write chip employing support ISO/IEC 14443A agreement, and market is most widely used, and buys the also MFRC500 of most convenient.

Anneta module comprises the module for reading and writing realization requisite coil of radio communication and match circuit, and the radio frequency module for reading and writing will rely on the magnetic flux of antenna generation for rfid card provides power supply, transmission information between radio frequency module for reading and writing and rfid card.For making the antenna normal operation, aerial coil 1 will connect by passive match circuit the sky wire pin of radio frequency read-write chip.

Described single-chip microcomputer STC89C52 is that connection by parallel control interfaces such as data line, address wire, control lines realizes to the control of MFRC500, and on the other hand, MFRC500 can use independently reading and writing signal wire or common these two kinds different parallel control interfaces connection single-chip microcomputer STC89C52 of reading writing signal line, and it also is different adopting the different corresponding bus timings of signal wire institute.

Shown in Fig. 2 single-chip microcomputer STC89C52 of the present utility model and radio frequency read-write chip MFRC500 connecting circuit figure, in circuit, what radio frequency read-write chip MFRC500 used is that independently the reading and writing signal wire is connected with single-chip microcomputer STC89C52, select in the mode of address wire, radio frequency read-write chip MFRC500 has used the multiplexing mode of data/address wire, and the data of the data of single-chip microcomputer STC89C52/address wire P00-P07 and MFRC500/address wire D0-D7 connects one to one.In addition, single-chip microcomputer STC89C52 adopts interrupt mode, introduces MFRC500 interrupt source by the INT0 pin, and the interrupting information that utilizes MFRC500 to provide interrupts control.

Radio frequency read-write chip MFRC500 modulates the signal that obtains sending according to the setting of its register to sending data, sends with the electromagnetic wave form of 13.56MHz by driven antenna that pin TX1 and TX2 drive by antenna.Rfid card in its radio-frequency region adopts the load-modulate of RF field to respond.Antenna reception is delivered to the reception pin RX of RC500 through antenna-matching circuit to the response signal of card, the receiver of chip internal carries out demodulation, decoding to received signal, and process according to the setting of register, at last data are sent to parallel interface and read by microcontroller.

As shown in Figure 3, in high-frequency filter circuit, in order to reduce the interference on the signal wire, used the EMC high-frequency filter circuit.Sky wire pin TX1, TX2, RX and the reference voltage VMID of radio frequency read-write chip MFRC500 pass through first high-frequency filter circuit, and then are connected with the match circuit of Anneta module.In the high-frequency filter circuit, inductance L 1, L2 and capacitor C 7, C8, C9, C10 have formed the filtering circuit of radio frequency read-write chip MFRC500 radio frequency transmit signal.Resistance R 1, R2 and capacitor C 5, C6 have formed the filtering circuit that receives signal.In order to reach good electromagnetic compatibility, when making printed circuit board (PCB) (PCB), the circuit of this part must be near sky wire pin RX, TX1, the TX2 of radio frequency read-write chip MFRC500.

And in its match circuit, for enough energy are provided to rfid card, must realize tight coupling between antenna and card, coupling coefficient is minimum for the 0.3(coupling coefficient is 0 o'clock, namely owing to causing complete decoupling apart from too far away or magnetic shielding; Coupling coefficient is 1 to be unity couping).Therefore aerial coil 1 employing diameter is the wire of 1mm, is designed to three 65mm that encloses * 54mm square antennas, and at this moment, the inductance that aerial coil produces has following formula to calculate: L=2 * I * ln ﹙ 1/D ﹚ * N

Wherein:

L is the inductance;

I is the length (i.e. the girth of a circle) of ring shaped conductor, and unit is cm;

D is the width of conductor, i.e. diameter of wire, and unit is mm;

N is the number of turns of coil.

The inductance value that can be calculated aerial coil 1 by above-mentioned formula is about 1uH.Reduce the loss as far as possible and radiation for the radiofrequency signal from the antenna component pin that aerial coil 1 is received, adopted antenna-matching circuit as shown in Figure 3 that it is carried out impedance transformation.The parameter of the capacitor C 1 of antenna-matching circuit, C2, C3, C4 is determined by the inductance value of antenna.Because aerial coil 1 inductance value of every different antenna circuit board reality always can be slightly variant, therefore used a tunable capacitor C0 at antenna-matching circuit, by adjusting tunable capacitor the reading/writing distance of every antenna plate is adjusted to the best.

Above-described embodiment only is the better embodiment of the utility model; but embodiment of the present utility model is not restricted to the described embodiments; other are any not to deviate from change, the modification done under Spirit Essence of the present utility model and the principle, substitute, combination, simplify; all should be the substitute mode of equivalence, be included within the protection domain of the present utility model.

Claims

1. a radio frequency identification card reader that is used for library management system is characterized in that: comprise main control module, radio frequency module for reading and writing and Anneta module; Described radio frequency module for reading and writing comprises radio frequency read-write chip and high-frequency filter circuit; The parallel control interface of described main control module is connected with the radio frequency read-write chip with control line by data line, address wire, described radio frequency read-write chip links to each other with Anneta module by high-frequency filter circuit, and described Anneta module comprises and radio frequency module for reading and writing match circuit that link to each other, passive and the aerial coil that links to each other with match circuit.

2. radio frequency identification card reader according to claim 1, it is characterized in that: described main control module comprises the STC89C52 single-chip microcomputer.

3. radio frequency identification card reader according to claim 1 is characterized in that: the radio frequency read-write chip MFRC500 of described radio frequency read-write chip employing support ISO/IEC 14443A agreement.

4. radio frequency identification card reader according to claim 2, it is characterized in that: described main control module also comprises the serial communication interface that is connected with the STC89C52 single-chip microcomputer.

5. radio frequency identification card reader according to claim 2, it is characterized in that: described STC89C52 single-chip microcomputer comprises 8k bytes Flash storer, 256 byte RAM storeies, 32 I/O mouth lines, WatchDog Timer, 2 data pointers, three 16 bit timing device/counters, 2 grades of interrupt structures of one 6 vector, crystal oscillator and clock circuit in the full duplex serial port sheet.

6. radio frequency identification card reader according to claim 3, it is characterized in that: there are 64 registers described radio frequency read-write chip MFRC500 inside, and uses independently reading and writing signal wire parallel interface and the multiplexing mode of data/address wire to be connected with single-chip microcomputer STC89C52.

7. radio frequency identification card reader according to claim 3, it is characterized in that: described high-frequency filter circuit is the EMC high-frequency filter circuit.

8. radio frequency identification card reader according to claim 3 is characterized in that: it is the wire of 1mm that the coil of described antenna adopts diameter, is designed to the 65mm of three circles * 54mm square antennas.