A prototype interface Sadhbh Doherty and I came up with one day hanging out at Opendesk.
With the idea of making a piece of furniture warmer and more personal, we decided to give a table a way to communicate via taps and vibrations. In this prototype the table replies with the same pattern with which the user knocks.
USER: "Morning!" TAP, TAPATAP
TABLE: TAP, TAPATAP [Good morning to you too!]
This code activates a solenoid with the same pattern received by the piezo, combining this and this circuit.