Contactless ID RFID card canteen meal selling system solution

To solve these drawbacks, our company has launched a radio frequency card canteen meal selling management system. The system uses radio frequency cards to replace the meal tickets currently circulated in the canteen. Before diners go to the canteen to eat, they first pay a certain amount of cash as a pre-purchased meal ticket, and the canteen management department writes the amount, name, number, etc. into the user card; when diners go to the canteen to eat, they only need to insert the card into the meal vending machine at each window, and the staff can enter the amount used, and the meal vending machine will automatically deduct the corresponding amount. When the amount of money in the card reaches the specified minimum line, the window machine will display it on the screen and beep, reminding the user to go to the designated place to add the amount to restore the use of the card.

ID radio frequency card canteen meal selling system, radio frequency cards replace traditional meal tickets, avoid the waste of manpower, material resources, and financial resources caused by the circulation of meal tickets, avoid the forgery and loss of meal tickets, eliminate the drawbacks of the outflow of canteen benefits and cross-infection of germs, and realize the daily and monthly financial settlement. The use and promotion of radio frequency cards have played a huge role in promoting the modernization of logistics reforms.

Introduction to RFID Card Technology

RFID card, also known as contactless IC card, was born in the early 1990s. It is a new technology developed in the world in recent years. It successfully combines RFID technology with IC card technology, solves the problem of passive (no power in the card) and contactless, and is a major breakthrough in the field of electronic devices. Due to its incomparable advantages over photoelectric cards, magnetic cards and contact IC cards, it immediately attracted widespread attention and was promoted and applied at an astonishing speed.

RFID card consists of IC chip and induction antenna, and is completely sealed in a PVC card with no exposed parts. The reading and writing process of contactless IC card is usually completed by radio waves between RFID card and reader. RFID card

itself is a passive body. When the reader reads and writes the card, the signal sent by the reader is composed of two parts: one part is the power signal. After the signal is received by the card, it resonates with its own L/C to generate an instantaneous energy to supply the chip to work. The other part is to combine the data signal to command the chip to complete data, modification, storage, etc., and return it to the reader. The reading and writing system formed by the radio frequency card has been greatly simplified in terms of hardware structure and operation process. At the same time, with the help of advanced management software, the offline operation mode makes the data reading and writing process simpler.

Compared with the contact IC card, the radio frequency card has the following advantages:

1. High reliability: There is no mechanical contact between the radio frequency card and the reader, which avoids various faults caused by contact reading and writing. For example: Faults caused by rough card insertion, insertion of non-card foreign objects, dust or oil pollution leading to poor contact. In addition, there is no exposed chip on the surface of the radio frequency card, so there is no need to worry about chip shedding, electrostatic breakdown, bending damage, etc., which is convenient for card printing and improves the reliability of card use.

2. Convenient and fast operation: Due to non-contact communication, the reader can operate the card within a range of 10cm, so there is no need to insert or remove the card, which is very convenient for users. RFID cards have no directionality when used. Cards can be passed over the reader in any direction to complete the operation, which greatly improves the speed of each use.

3. Anti-collision: RFID cards have a fast anti-collision mechanism that can prevent data interference between cards. Therefore, the reader can process multiple RFID cards "simultaneously". This improves the parallelism of applications and invisibly improves the working speed of the system.

4. Suitable for a variety of applications: The storage structure of RFID cards allows it to be used for multiple purposes and can be applied to different systems. Users can set different passwords and access conditions according to different applications.

5. Good encryption performance: The serial number of the RFID card is unique. The manufacturer has solidified this serial number before the product leaves the factory and it cannot be changed. A two-way authentication mechanism is used between the RFID card and the reader, that is, when the reader verifies the legitimacy of the IC card, the IC card also verifies the legitimacy of the reader. The RFID card must be mutually authenticated with the reader before processing, and all data is encrypted during the communication process.

RFID card system parameters

RFID cards meet international standards, with a data retention period of 10 years and unlimited reading times. The radio frequency card has no power supply, but has its own antenna. It contains encryption control logic circuit and communication logic circuit. The communication between the card and the reader adopts the internationally used DES and RES confidentiality cross algorithm, which has extremely high confidentiality performance.

Working frequency:

Anti-collision: Multiple cards can be processed at the same time. Reading and writing distance: within 20MM (related to the shape of the antenna) Data can be transmitted conveniently and quickly2

Half-duplex communication mode2

The following mechanisms are used to ensure data integrity during wireless communication

Support multi-card operation

Anti-collision mechanism: Multiple cards can be processed at the same time, and sudden reading or writing or reading and writing interruption can be prevented when processing cards. Dynamic reading and writing When a certain card is processed, other cards can enter or leave the RF area. Fast anti-collision protocol Each additional card only adds 1ms to the entire processing process

u Material: PVC

u Dimensions: in accordance with ISO10536 standard

u Working temperature: 20℃ to 50℃ (humidity is 90%)

u No battery: wireless transmission of data and energy

u Chip processing technology: using high-speed CMOSEEPROM technology

u Components: a chip and a simple coil each Security:

u Mutual authentication (ISO/EC DIS97982)

ü All data are encrypted during the communication process to prevent signal interception

. The serial number of each card is unique in the world.

Typical transaction process < 100ms.

Working principle.

The electrical part of the card consists of only an antenna and ASIC, without other external devices. Antenna: The antenna of the card is a coil with only a few windings, which is very suitable for packaging into ISO cards. The working principle of the radio frequency card is: the reader sends a set of electromagnetic waves of fixed frequency to the radio frequency card. There is an LC series resonant circuit in the card, and its frequency is the same as the frequency emitted by the reader. Under the excitation of the electromagnetic wave, the LC resonant circuit resonates, so that there is a charge in the capacitor. At the other end of this capacitor, there is a unidirectional electronic pump connected to send the charge in the capacitor to another capacitor for storage. When the accumulated charge reaches 2V, this capacitor can be used as a power supply to provide working voltage for other circuits, transmit the data in the card or receive the data of the reader.

Confidentiality.

The confidentiality performance of the radio frequency card is very good: unique card serial number, transmission data encryption.

RFID card charging machine

Technical indicators

Settlement time < 1 second, offline buffer 5000 records, power consumption < 10W, power supply voltage 220V±10%,

communication interface RS-485, reliable communication distance 1200 meters, communication speed 9600BPS

RFID card charging main control system

1, financial management daily settlement and monthly settlement

The database security is impeccable. The financial part of the meal sales management software is a standardized financial software. It uses a SQL2000 dedicated database, with different encrypted storage of each data, set check bits and database association check, which completely eliminates the possibility of financial personnel modifying the database.

The project statistics are complete. The business conditions of the day or meal are counted according to any time period, realizing various functions such as "same-day settlement", "business statistics", "log retrieval", and "issuance of monthly subsidies".

Easy printing, clear at a glance. The report vouchers and operation journals for account opening, account cancellation, card replacement, error correction, monthly subsidies and other account content modifications in the management system can be immediately counted and quickly printed.

Transaction error correction, report recording, safe and thoughtful. In financial management, the management system software has set up an important error correction function, which solves the problem of only cash refunds for erroneous operations after card removal.