A New Design and Implementation of an Attendance Checking Node for Coal Mines

A novel design and implementation of an attendance checking node for coal mines based on the CAN bus is presented in this paper. Hardware circuits and programming methods for the attendance checking node are discussed, including the single-chip computer with CAN controller AT89C51CC03, the CAN bus transceiver TJA1050, the large capacity DataFlash memory, the real-time clock DS1302, the voice chip ISD2560 and the card-reading circuit in Wiegand format. All the extended hardware satisfies the requirements for intrinsically safe circuits (GB3836.4-2000) and intrinsically safe authentication promoted by the national explosion-proof institute. Further, the software programming methods for the CAN controller (AT89C51CC03) and the implementation of the CAN communications protocol are presented as well.