Makey Makey turns a banana into a keyboard

Place several bananas on a desk and attach alligator clips. Hold the ground connection with one hand and touch a banana with the other, and the computer receives a keyboard input. Makey Makey is an invention kit that turns everyday objects into input buttons. The banana itself does not produce piano sounds.

The Classic board connects to a computer as a USB keyboard or mouse. Touching a connected object completes the circuit and sends an input such as the space bar or an arrow key. If that key is assigned to a piano note in the computer program, a note sounds; if it is assigned to jump in a game, the character jumps. The program determines the sound, while the connected object determines what you touch.

Your hands and the objects form part of the electrical circuit. Along with bananas, suitable materials include aluminum foil and conductive clay. Pencil lines can also work, though simply drawing anything on paper is not enough. Detection depends on the material used for the line and how it is connected.

Instead of being handed a finished controller, you get to decide what the buttons should look like. If a small button is awkward to press, you could use a wide piece of foil. You could also complete a circuit together with a friend. Deciding which action becomes a keypress is part of making the controller.

Different models detect input differently. Classic uses the opening and closing of a circuit, while GO detects changes in capacitance. The banana and ground-wire example here applies to Classic. The input board and the program running on the computer also have separate jobs.

Replace the banana with foil and the computer may still receive the same keypress, but your hand moves differently. What you make with Makey Makey is less a new key than a new way to reach it.