Digital Inputs – Making a Paper Piano

To create digital inputs for the Sound Clippy board we need to create an electrical switch which can be turned “on” and “off”. In this case, “on” means connected to GND and “off” means disconnected from GND.

Digital Inputs

Each digital input on the board can be triggered individually. Each port has a number printed on the board indicating which port it is.

The [mm-digital] object uses the number after the object name to select the port. For instance, if you want to read port D2, add a new object and type [mm-digital 2] – you should see this:

Screen Shot 2015-07-13 at 11.33.51 PM

With the Sound Clippy board connected, when a digital input is connected to GND through an alligator clip or with another conductor you should see an “X” in the corresponding [mm-digital #] object toggle box.

Alligator clip switch

Open up simple-synth.pd from the modular-muse/examples/sound-clippys folder and connect to the board. (TODO: how to connect)

– Clip an alligator clip to one of the GND  ports (they’re all the same).

– Touch the other end of the alligator clip to one of the digital pins


When you touch the alligator clip to the digital pin you’re making an electrical connection between the input pin and ground which the board can detect. This is sent to the corresponding [mm-digital] object.

Paper Piano

You can extend the alligator clip wires by connecting to other conductive materials. Copper tape is a good conductor and is easy to work with.


– construction paper

– copper tape

– Sound Clippys Board

– alligator clips


To build a successful “piano” we need to be able to connect the digital pins to ground individually. This will be done by cutting individual “keys” into the paper which will become the triggers or buttons.  First its good to decide on the size and cut the basic shape. I’m going to make a basic rectangle piano with 6 keys.

Basic Design

Cut down to size and figure out how the “buttons” will be made. For this simple example I cut the construction paper to a small rectangle about 6″ x 3″, then I folded it in half the long way so it is now 6″x1.5″.


Cut the individual keys


Run the ground “wire”


All the keys need to be able to connect to ground (GND). Since all the keys are in-line I just need to run one long piece of copper tape which will go under all of the keys.

Keep the tape a little longer than it needs to be so it can be folded around the back. This makes for a better surface to connect to with the alligator clips later.


Now run copper tape for each individual key. Make sure that the tape is long enough to fold around to the back side of the key where it will make contact with the GND copper tape.




Connect the GND to the ground copper tape which runs under all the keys.

Connect the individual keys to the desired digital inputs.

The example patch “simple-synth” makes each digital input control a different pitch to be played.

The fun has just begun!

Try other examples in the sound clippys example folder to explore different sounds and ways of using digital inputs.

One thought on “Digital Inputs – Making a Paper Piano”

Leave a Reply

Your email address will not be published. Required fields are marked *