Chris Holden has written an article on their new door entry system at BuildBrighton:
The basic idea is this:
- A keyfob is presented to the reader and the serial number read from it.
- The keyfob number is displayed on the character LCD.
- This is sent (via the ethernet module) to a URL to validate the serial number and the web site returns data to say who the key belongs to
- If data is successfully received from the website, it is stored in the local eeprom chip
- If there is a fault and no data can be received from the ‘net, the eeprom is searched, looking for a matching keyfob number. If a match is found in eeprom, the data is read out and handled as if it had just come from the website.
- If the keyfob belongs to a valid user, their name is displayed on the character LCD and a relay is activated to open the door.
- If the serial number is not recognised, a “not recognised” message is displayed in the lower part of the LCD display.
Check out the video after the break.
Schematics for RFID door entry system.