Magnetic Card Reader Made of PIC12F675

The project matches a PIC12F675 microcontroller to create a magnetic card reader while using track 2 data.

The PIC12F675 is a power and easy-to-program CMOS Flash-based 8-bit microcontroller having an architecture into an 8-pin package and features 4 channels for the 10-bit analog to digital converter, 1 channel comparator, and 128 bytes of EEPROM data memory. This device is easily adapted for appliances, industrial, automotive, and consumer entry-level product applications that require field re-programmability.

A magnetic head on a spring mechanism is being provided by the unit along with low level head signal amplifiers and data slicers. The card presence, clock, and data are also provided through the three signal lines coming from the device. It will draw about 50mA at 5V when a card is read actively.

The appearance of data from the unit is in track-2 format which is 4 bit plus odd parity data. By adding HEX-30 to each nibble, the data is readily converted to ASCII. The in-circuit programming is allowed through a protoclip because of the pair of 10K resistors on GP0 and GP1. By robbing the negative voltage from the PC, the RS232 levels are generated.