If a numerical combination system, keyswitch or self-discipline isn't enough to keep someone out of your treasure box - consider following Basil Shikin's instructions on how to make a lock that is triggered by a specific piece of music. Basil uses an Arduino, an electret microphone, and various electronics installed into a customised box. Matched with some nifty coding of the Goertzel Algorithm which is used to detect a particular frequency in a sounds, the system can detect a particular tune and then action the lock (or not). For example:
For those who would like to reproduce this project, you can start with our Arduino-compatible boards such as the Leostick, and our MIC sound input module, then follow Basil's instructions here.
