Contactless IC card, also known as radio frequency card. It successfully solved the problem of passive (no power in the card) and contact-free. It is a major breakthrough in the field of electronic devices. It is widely used in electronic wallets, smart cards, campus cards, channel charge control, automatic bus ticketing, automatic parking fees, canteen sales, attendance and access control, scenic spot charges, hospital charges, etc. Cards include membership card, access control card, charge card, consumption card, bus card, student card, hospital visit card, scenic ticket card, point card, stored value card, shopping card, water card, etc.
Contactless IC cards are mainly MIFARE ONE cards (that is, M1 cards). M1 card main indicators: The capacity is 8K bits, the EEPROM is divided into 16 sectors, each sector is 4 blocks, each block is 16 bytes, block is the access unit, and each sector has an independent set of passwords And access control. Each card has a unique serial number, which is a 32-digit number. It has an anti-collision mechanism and supports multi-card operation. It has no power supply, has its own antenna, and contains encryption control logic and communication logic circuits. The data retention period is 10 years. It can be rewritten 100,000 times and read infinitely. Its operating temperature range is -20 ℃-50 ℃ (temperature is 90%). The operating frequency is 13.56MHZ. The communication rate is 106KBPS. The reading distance is within 10mm (related to the reader).
The working principle
The reader sends a set of fixed frequency electromagnetic waves to the M1 card. There is an LC series resonant circuit in the card, whose frequency is the same as the frequency emitted by the writer. Under the excitation of electromagnetic waves, the LC resonant circuit resonates, so that there is a charge in the capacitor. At the other end of the capacitor, a unidirectional electronic pump is 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 to transmit the data in the card or access the data of the reader.