Alex Glover has demonstrated an interesting form of electronic lock... instead of using a keypad or RFID, Alex's system uses an accelerometer. An Arduino is programmed to measure the values from the accelerometer - and when the device is tilted in a certain sequence this is detected by the Arduino and an action can be take, for example opening a solenoid to allow the box to be opened. A quick demonstration is in the following video:
This tiny 3-axis accelerometer module can operate in either +/-1.5 g or +/-6 g ranges, giving your project the ability to tell which way is up. Ideal for robotics projects, tilt sensors, vehicle data loggers, and whatever else you can dream up. For more information and to order, click here.