ï~~
NON-COCHLEAR SOUND
___ LJUBLJANA 9.-14. SEPTEMBER
AlRduino: An Inexpensive DIY MIDI Wind Controller
Timothy Anderson
University of Montana
32 Campus Drive
Missoula, MT 59812
[email protected]
ABSTRACT
The AlRduino is a hardware MIDI controller featuring a bidirectional breath pressure sensor that has the ability to
control different parameters by inhaling and exhaling through
the sensor. The controller also features four videogamecontroller thumbsticks for addition expression, along with
eight trimpots for extra versatility. Through these two unique
types of sensors, the AlRduino allows the performer a
versatile and unique method of controlling his or her music.
This MIDI controller is easy to assemble from inexpensive
parts, and is open source in both code and circuitry
schematics.
Keywords
Arduino, MIDI, Electronic Instrument, DIY, Breath Pressure
Sensor, Thumbsticks
1. INTRODUCTION
As both a musician and an avid computer programmer, I
often see other musicians express confusion about their
electronic instruments. While they can easily accomplish
tasks with their instruments, they seldom understand how
their hardware works. My goal through this project is to use
the Arduino microcontroller, some simple, cheap, and easy to
use sensors, and one unconventional breath pressure sensor to
enable musicians to easily build their own MIDI controllers,
and learn about the controller's structure in the process.
2. AIRDUINO: ABOUT THE CONTROLLER
2.1 Arduino at the Heart of the System
As the name AlRduino implies, the MIDI controller is built
around the Arduino Uno Microcontroller board. Because of
the relatively small price of the board, ease of hardware
implementation, and wealth of online resources, the Arduino
infrastructure was an obvious choice. At a price of thirty USD
at time of writing1, the board is an affordable microcontroller.
Additionally, Arduino is easy to use in development, as no
soldering is required. Instead, the Arduino is equipped with
pin slots that wires can be inserted into. Because knowledge
of complex circuitry isn't a prerequisite to working with the
Arduino, it becomes much more accessible to musicians
interested in building a MIDI controller. The tutorials and
examples on Arduino.cc work to further bridge the gap of
technical understanding required to construct a MIDI
instrument. By having access to a plethora of tutorials on the
hardware and software involved, even those with little
circuitry experience can easily find answers to any problem
they might have while constructing their own AlRduino.
2.2 Bi-Directional Breath Pressure Sensor
When I started working on this project, I was determined to
create an interface that was simple and utilitarian, yet had
some unique function that couldn't be found elsewhere in
MIDI controllers. However, since my main instrument is
Saxophone, the first few ideas for this project looked similar
to the Electronic Wind Instrument (EWI) by AKAI2. In order
to distinguish the AlRduino from this well-established
counterpart, the AlRduino was equipped with a specialized
breath pressure sensor that is able to read both positive and
negative pressures. What this means to performers is that the
pressure sensor sends one MIDI continuous controller for
blowing through the device, and a different one for inhaling.
By using two MIDI continuous controllers, new possibilities
open up for the electronic musician. By linking inhaling and
exhaling to the volume of two synthesizers in a Digital Audio
Workstation (DAW), it is easy to add dynamics to an
otherwise static line of music. Additionally, by changing the
1 http://www.sparkfun.com/products/10356
2 http://www.akaipro.com/ewiusb
Figure 1. A top-down view of the AlRduino.
The four thumbsticks each send MIDI data
based on their current X and Y positions, and
return to the center when not being
manipulated.
CKV
