This project was motivated only because I had a Basic Stamp 2px, RFID reader and Smart Card reader/writer sitting around doing nothing. All these were from Parallax. I used an old 20x4 serial LCD and a project box from RadioShack to make this reader a handheld device.
PBASIC source code is in the Attachments section at the bottom. There is very little original code, I copied and pasted the examples for the RFID and Smart Card reader from Parallax then just basically polled the two devices to see if anything was coming in at the time.
Note that the Smart Card reader communicates via serial so if you unplug the card before the display says 'Done!' the program will freeze.
This project uses 6 I/O pins on the Basic Stamp 2px. The Smart Card reader uses 3 pins, one for card detect, serial data I/O and serial data clock. The RFID reader uses two pins, card detect and serial data I/O. The last pin is serial data for the LCD screen. For the complete project I added a 5V regulator because I'm using a 9V battery to power the unit. All devices are 5V so no more power issues there.
Using the sample code from Parallax as mentioned above, I commented out the DEBUG commands and replaced them with serial commands to the LCD. The full explanation is in the video at the bottom.
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Upgrades! Added 4 buttons. This allows RFID tags to be saved to the bs2px EEPROM as well as dumping EEPROM on to the Smart Card itself. Also allows USB to PC connection for manual Smart Card data entry.
Switched to the ATMega328 with Arduino bootloader. Trying to create a sales-worthy device I've removed the expensive LCD screen for 3 LEDs and a smaller case: