the link i had given above contains may good project like RFID , GSM, GPS based projects… you can see them amd modify them according to your need or application..
like for RFID the toll plaza example or attaindace based example.. every thing is expalined on the that link…
lets say if you wnt attandance system based on RFID.. it has interfacing of eeoprom lcd rfid etc.. so even each interfacing is seperalty explaind on the link…