Enlight the world with a tangerine!

During the Linux Day Milan 2016, an inportant event dedicated to free and open source software in Italy, we shown an interactive station that used capacitive sensors to detect user touches.

elettrodes

Some electrodes created with a special electric paint by BareConductive are painted on a normal sheet of paper.

These electrodes allows an Arduino and some others circuits connected to it to send messages to a computer. Messages are interpreted and used to created real time graphics and sounds.

station 2

To create a different feeling we have added a special electrode: a tangerine!

bimbi 3

If you touch it you will see the world lamp to light up while a new interesting sound is generated.

bimbi 1

bimbi 2 bimbi 4

How it works?

The heart of this station is an Arduino Mega. Inside it a program to make it able to talk with an Adafruit capacitive breaout board which uses the MPR121 to detect electric signal from capacitive sensors (the MPR121 is the same chip mounted on the BareConductive Capboard).

The Arduino Board is placed inside a control unit box with the relay module. This relay module gives Arduino the capability to command electric devices that needs to be powered by the 220V power supply.

Inside the main control box there is place also for a BlueSmirf bluetooth modem thanks to which Arduino is able to communicate with other devices from distance.

The Adafruit capboard is placed inside a little satellite box that we connect to the main control unit box using a RJ45 cable.

7 capacitive electrode sensors are created using the BareConductive electric paint on a normal sheet of paper then they are connected using clips soldered with a little cable to the capboard.

The eighth electrode is a tangerine we have skewered with another clip, it connect to the capboard too.

The program is studied in a way that the Arduino closes the relay when the capboard detects a touch on the tangerine so to light up the world lamp connected to the relay module.

station 4

At the same time Arduino sends a message via the bluetooth serial communication to a Processing sketch running on a near laptop.

This sketch has the task of translating this message into an OSC message and send it through as ethernet cable to a another laptop. The latter runs SuperCollider scripts and produces sound in real time accordingly to the incoming OSC messages.

The tangerine is not the only electrode that produces sounds but there are also other 3 circular shaped eletrodes that are able to trigger OSC messages addressed to SuperCollider.

In addition there are 4 more electrodes: they have a square shape and they are able to communicate Processing to draw new coloured shapes on screen.


Issues

More relay

Originally this interactive station was though to have 3 relays instead of one. One of these was driven by a little electret microphone while the third had to be commanded by Processing through the BlueTooth connection.

station 2 original

We have had some trouble using 3 relays with the Adafruit capboard and, ultimately with the mic also so we decided to simplify the station.


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