How to Play the DUbone

Week 7 Progress

Initial assembly to check fitment of printed and electrical parts (no electronics connected yet)

Designed hand strap and associated printed parts.

Sourced parts for audio amplifier (Sparkfun breakout board with Radio Shack speaker)

The acrylic pieces are snapped into the 3D printed shells

Fitting the parts into the lower half of the case

Everything fits!

Week 8 Progress

First assembly of electrical components for testing.  The audio amplifier board and loudspeaker have not yet been installed  (still in the mail).

Last minute relocation of the headphone jack for preliminary demonstrations.  In the background the (still to be attached) hand strap is visible.

Tavi and Zack test the DUBone

Dr. Noh listens to a demo performed by Tavi

The carrying strap is epoxied into place with Loctite

Week 6 Progress

Assembly

• 3D printed pieces completed: reel for reel assembly (with mounted potentiometer) and wind sensor housing
• Obtained on/off switch and three push buttons which were mounted on laser cut acrylic panels
• Designed inner layout of toy and placement of major parts
• Designed and produced pull handle for string

Completed CAD design showing 2-part outer case design and location of major assemblies

The pull for the string potentiometer assembly is shaped like the letter D in honor of Drexel

Completed pull-string potentiometer assembly with pull tab

Pull string potentiometer assembly and control panels

Week 5 Progress

Design Adjustments

• Will have acrylic and 3D printed pieces
• Use of laser cutter to obtain piece to mount potentiometer
• Camcorder-like strap on outside, for easier grip
• Drafted possible configurations of inner parts
• 9V battery
• Potentiometer and pull-string reel
• Spit Valve
• Outer shell will have buttons/touch sensors to allow for variation in sound
• Vibrato
• Portamento
• Timbre cycle button
• On/Off switch

Troubleshooting Microphone

• Responds to breath/blowing into sensor
• Unexpected movements create wind, also noticed by sensor
• Design of wind sensor housing may be critical for producing a usable signal on the microphone.
• Switching to an adjustable-gain microphone board may solve sensitivity
• Testing Arduino output with iPhone earbuds
• Changes pitch; plays a chromatic scale
• Adjustment of programming for a smoother sound
• Code to specifically output a major scale

Testing the wind sensor software

Wind Sensor with 3d-printed housing

Printing the reel on the MakerBot Replicator II

Prototype reel assembly.  The released spring force broke the internal end stops of the potentiometer during testing.
This pointed out the need for some sturdy plastic end stops on the 3D-printed reel.  These will engage with the spring fixing screw and prevent potentiometer damage.

Using CAD to arrange major components of the DUBone helps to determine the shape of the case design

Week 4 Progress

Pull-string controller

• Keeping the instrument as aesthetically close to a trombone as possible
• Designing a spring-loaded reel to be fitted onto a potentiometer

1. Approximate 2 octave range
2. Will unwind like a spool; spring attached to potentiometer
3. Difference in voltage -> indicates pitch of note output

AutoCAD sketch of inner reel

Week 3 Progress

Mouthpiece

Comprised of: microphone, interchangeable mouthpieces

• Electret-condensor microphone with integrated amplifier
• Interchangeable mouthpieces, similar to hookah tips
• Produces an output proportional to intensity with which player blows into instrument 
• Necessary to implement a drain/"spit valve" to remove moisture from inside

Pencil sketch of wind sensor housing cross section, with Sparkfun condenser microphone breakout board.  The board features a built in microphone amplifier.
(Click to enlarge picture)

AutoCAD sketch of wind sensor housing.  This holds the mouthpiece and microphone board as well as providing mounting holes to the final assembly of the instrument.
(Click to enlarge picture)