Uwi

3D-printed motion-controlled wind instrument
Physical Prototyping, 3D Printing, Arduino
Nov–Dec 2018

Quick Summary

  • Inspired from musicians' expressive movements in performances, I would like to make "Uwi", an experimental wind instrument where musicians actually have to move to make music.
  • The form of the instrument was ideated through sketching and iterative modeling.
  • The mechanism of Uwi were implemented through Adafruit Circuit Playground, an Arduino platform.
  • The design were then 3D modeled using SolidWorks and 3D printed to test the interaction.

My Roles

  • Solo Project: Designed the interaction, Sketched, Created sketch models to visualize te form, Created 3D models for fabrication of the physical prototype through 3D printing, Coded the software on Adafruit Circuit Playground.

Details

Team Tae Prasongpongchai (Me)
Tools Sketching, ­Iterative Modeling, ­SolidWorks, ­3D Printing, ­Arduino
Purpose Class Project, CS8803-PP Physical Prototyping at Georgia Tech, Fall 2018, Noah Posner
Timeline Nov–Dec 2018

Video Demo

Design Question

Despite arguably not contributing much to the actual sound of their music, expressive movements made by the musicians are key parts of most music performances.

“What if they ‘have to’ move to even make music?”, I wondered. Inspired from that fact, in this project, I would like to create “Uwi”, an experimental instrument where performers actually have to move in order to play a piece.

Overview of the Process

Analyze Thumbnail

1. Coding

  • Adafruit Circuit Playground
  • Deciding on Sensors
  • Arduino Coding
Design Thumbnail

2. Form Ideation

  • Sketching
  • Iterative Modeling
Dev Thumbnail

3. 3D Modeling

  • SolidWorks Modeling
  • SolidWorks Assembly
Dev Thumbnail

3. 3D Printing

  • Iterative Design

Technical Considerations

Adafruit Circuit Playground

Adafruit Circuit Playground was the main electronics tool used in this project. It is an Arduino board packed with lots of built-in sensors and output devices including two push buttons, a switch, a microphone, a thermometer, a light senser, capacitive touch pads, an accelerometer, LEDs (neopixels), and a speaker.

Considering the design question of incorporating movement into music-making, I utilized these components available on the board:

  • Accelerometer: For detecting movements.
  • Microphone/Sound Pressure Sensor: As the trigger point for sound. I decided on making the instrument a wind instrument as it fits well with the available tool and it makes the instrument more challenging to play.
  • Buttons: Another input of the instrument, providing more manipulation of the sound.
  • Speaker: For sound output.
  • LEDs: As secondary feedback to the performer.

These elements were located on different areas of the board as shown below.

Adafruit Circuit Playground, photo courtesy of Adafruit
Adafruit Circuit Playground, photo courtesy of Adafruit
Circuit Playground input/output, photo courtesy of Adafruit
Circuit Playground input/output, photo courtesy of Adafruit

Coding

The core logic of the instrument was coded using Arduino C++ on the Arduino IDE. Circuit Playground’s sensors and output were used to make a wind instrument which is controlled by user’s motions.

Coding Uwi core logic.
Coding Uwi core logic.

Form Ideation

With the code working, a housing for the electronics were then designed. The form of the instrument was ideates through multiple methods including sketching and iterative modeling.

Sketching

Sketches were drawn to brainstorm the forms of the instument. The ideas were based on the shape of the Circuit Playground and the final pose of the musician performing with this instrument.

Sketches for form ideation of Uwi.
Sketches for form ideation of Uwi.
Sketches for form ideation of Uwi.

Iterative Modeling

Sketch models were created from cardboard to help visualize the actual scale of the design. It also shows how electronics will fit into the form, helping me find the configuration in which the electronics should be placed.

This process helped me realized that the battery pack should be arrange with the long edge parallel to the long side of the instrument as doing otherwise would make the body of the instrument too wide.

Creating form for side view at 1:1 scale
Iterations of forms in cardboard model
Cardboard model visualizing top view at 1:1
Fitting electronics into model

3D Modeling

The design were then modeled in SolidWorks for 3D printing. Each part were then assembled virtually also in SolidWorks to see if they fit together and to check if there are enough indexing features.

Screenshots from the 3D modeling process in SolidWorks
Screenshots from the 3D modeling process in SolidWorks
Exploded view of the design showing assembling steps
Exploded view of the design showing assembling steps

3D Printing

1st Iteration

Details

  • The initial design has longer windway and sound holes are in the front of the instrument.
  • The top housing piece has light walls intended to direct LED lights to the upper surface of the instrument. The intended effect from this design feature is a flat top surface which lights up as letter forms to indicate the note to be played.
  • The model was 3D-printed in PLA as material.
What Worked?
  • Friction fit worked well. Parts can be held together reliably without any screws.
  • Battery and board fit well. The parts fits in place without being too loose.
What Didn't Work?
  • Despite the wind chamber designed, the air flow was too soft at the microphone, resulting in an unstable blow detection.
  • Lights from LEDs barely went through the top surface as the light walls were slanted and the top surface was too thick.
  • Sound hole was too far away from the speaker, resulting in a soft, muffled output sound.
  • Aesthetic issue: the placement of the buttons and the sound holes formed a *spooky face* that is difficult to be unseen once spotted.

2nd Iteration

What Was Changed?

  • Issues found in the 1st iteration were addressed: light walls were redesigned, the windway was shortened, the sound holes were moved, and an additional wind wall that directs the blow towards the microphone was added.
  • On the top surface, pitch letters were shown visibly with some decorative lines to make the instrument more visually pleasing.
  • The model was 3D-printed in ABS due to unavailability of the PLA printer used for the 1st iteration.
  • In preparation to the material change, tolerance values were adjusted to be wider to compensate with possible shrinkage of ABS prints.
What Worked?
  • The instrument looked better.
  • The visible pitch letter gives better signifiers for the users to understand that this is a musical instrument.
  • LED effects became much clearer.
  • Air flow and sound output was better than the 1st iteration.
What Didn't Work?
  • Air flow is still sometimes unstable
  • Due to the tolerance compensations, parts became too loose. The housing cannot hold itself together without falling apart.
  • When this prototype shown to other people, they cannot try it as it already had mouth contact from initial testing.

3rd Iteration

What Was Changed?

  • No changes were made in terms of overall form. The top piece was brought form the last iteration to save printing costs.
  • Smaller tolerance values for better friction fit.
  • Extra foamcore piece to direct the windway even more.
  • Added an extra mouthpiece which allow users to plug a plastic straw and let other people try the instrument.

The Final Design

Uwi: Final Design
Uwi: Final Design

Features

Sites Information Screens

Blow for Sound

  • Uwi is a wind instrument. The sound activates when the device detect a blow from its microphone.
  • The form of the instrument gives affordance of blowing through the mouthpiece at the back of the instrument.
  • Sound holes were placed right on top of the speaker to allow output sound to pass through.
  • The internal windway directs the wind from blowing directly to the microphone.
Tilt around X axis to change pitch

Changing Pitch

  • Users can tilt vertically to change the pitch that the instrument will play once blown.
  • The higher the tilt, the higher the notes. The notes are in C Major scale.
  • LED lights will lid up to let the performer knows which note it will play so that the performance can be carried out reliably.
Tilt around Y axis to play sharps & flats

Pitch Modulation

  • Users can tilt in another direction to add sharps or flats into the pitch.
  • This enables the instrument to play in full chromatic scale.
  • LED lights will also indicate the pitch modulation.
Press buttons for octave shift

Octaves

  • To play a wide variety of songs, we will need more than one octave.
  • Users can hold the buttons for octave shift: left and right button for lower and higher octaves, respectively.
  • This makes the range of this instrument 3 octaves wide from B2–C#5
  • Users can hold the buttons for octave shift.
  • Colors of the LED changes according to the current octave it will play.
Plug & Share

Plug & Share!

  • New and flashy technology invites people to try and experience, but wind instruments are not the best to share with other people.
  • A special mouthpiece were made so that users can plug in a plastic straw and let other people experience the instrument for themselves.

What I Found From This Experimental Instrument

  • The mapping between tiling angle and the output pitch was natural and can be learned quickly.
  • The skill floor of Uwi (how hard it is to get started) is relatively low, compared to some wind instruments such as a saxophone, but it is also not as straightforward as pressing a keyboard key or humming into a kazoo.
  • The skill ceiling (how good can one get at this) can be high as it requires precision to play a song correctly and reliably. It appears that it will take a significant amount of time to master the instrument.
  • These level of skill floor and ceiling is what I think makes the instrument fun to play as it is challenging but not too difficult to play.
  • Precision in movement required to play an Uwi might limit musical expressions but it might also make a Uwi performance interesting to watch.
  • To promote expressiveness in music made with Uwi, other features such as volume control and vibrato should be added.

Next Steps

  • The sound produced from the current prototype is still too soft for open environments, future iterations should include experimenting with other types of speaker for better sound.
  • It can be interesting to create a characteristic timbre for Uwi to distinguish it from other electronic instruments.
  • The microphone sometimes tends to wear off after a few uses. Future iterations should experiment with other type or position of microphones.
  • In this current prototype, the instrument must be almost totally disassembled for battery replacement. This is also a room for improvement for future prototypes.

What I Learned From This Project

  • I experienced the process of designing an interactive physical prototype/product.
  • I learned how iterative design plays a significant role in improving the user experience of a product.
  • I learned about the features and limitations of electronic hardware.
  • I learned how to design a physical form for 3D printing to minimize fabrication cost and time.
  • I learned about the feature and limitations 3D printing methods.
Uwi