DIY LEGO ATM Machine
The NXT ATM Machine is built entirely from Lego parts and functions just like any other ATM machine.
The NXT ATM Machine is a fully functional ATM built entirely from LEGO parts and a RFID sensor. The machine was developed by Ron McRae who programmed it in the Not eXactly C (NXC) language. The machine can spit out change, take notes, keep track of different accounts and even retain the ATM card if wrong PIN is entered thrice. It has a functional numeric keypad that uses a combination of touch and light sensors.
Here's a video demonstration of the ATM machine:
The NXT Step