Friday, 21 March 2014

Schematics for RFID door entry system

Our door entry system - rather unusually - uses a mix of PIC and AVR microcontrollers; the AVR acts as a serial/UART-to-ethernet gateway and does little else. Most of the work is done on the PIC, but when it needs to send and receive data to/from the 'net, it passes it over to the AVR via serial.

We programmed the AVR by putting an ATMega328 DIP into an early revision of a full-sized Arduino Duemilanove board, uploaded a sketch using the Arduino IDE, then popping the chip out of the socket.


Here's our schematic for the entire entry system - an RFID reader, a 24C256 eeprom, PIC16F886, 16x2 character LCD, LM7805 voltage regulator, 5v coil relay, a few transistors and ENC28J60 UART-to-ethernet module