Ukulele Easy Fret by rhammons716

Last crawled date: 3 years ago

BACKGROUND:
• Project originally developed in Spring of 2019 at Tennessee Technological
University in Dr. Stephen Canfield’s Dynamics of Machinery course.
• Finalist in the 2019 Eagleworks Business Competition and winner of the Clouse-
Elrod Foundation Social award.
• The Easy Fret is intended to assist individuals with motor disabilities play the
ukulele and educate people without disabilities how to play the ukulele by allowing
complex chords to be played with a single finger.
• This project is meant to be open source. Please feel free to make design
improvements (.stp files provided). It’s meant to be provided to local communities by
colleges and high schools that have access to 3D printers. The Easy Fret only fits a
Mitchell MU40NT Concert Ukulele at this time.
• Please contact me at rhammons716@gmail.com for any questions.
V1 EASY FRET:
• Parts:
• 1 x Flexible Plate [TPU]
• 1 x Hard Plate [PLA]
• 1 x F Key [PLA]
• 1 x G Key [PLA]
• 1 x am Key [PLA]
• 1 x C Key [PLA]
• 1 x Head Mount [PLA]
• 1 x Neck Mount [PLA]
• 2 x 91292A197_TYPE 18-8 SS SOCKET HEAD CAP SCREW [McMaster-Carr]
• 2 x 94545A225_18-8 SS WING NUTS [McMaster-Carr]

• Improvements:
• Improved mount installation by making the mount able to flex outward with a
compliant mechanism. This allowed for easier installation.
• Improved rigidity by adding a PLA plate that press fits into the flexible plate. This
improvement yielded more consistent beam motion by only allowing the beam to
flex instead of the entire plate.
• A cutout was added to improve flexible beam travel. This modification was
intended to work like a four Bar linkage. In a parallelogram four bar linkage the
intermediate link (link that connects the input and output link) stays parallel with the
fixed base link.
V2 EASY FRET:
• Parts:
• 1 x Flexible Plate V2 [TPU]
• 1 x Hard Plate V2 [PLA]
• 1 x F Key V2 [PLA]
• 1 x G Key V2 [PLA]
• 1 x am Key V2 [PLA]
• 1 x C Key V2 [PLA]
• 1 x Head Mount V2 [PLA]
• 1 x Neck Mount V2 [PLA]

• Improvements:
• The McMaster-Carr hardware was removed so the Easy Fret could be fully 3D
printed and not depend on any other hardware.
• After initial feedback from a classroom, the mounts were redesigned to be a
press fit into the flexible plate. This allows for quick installation and removal.
• A snap fit was applied to the C and am key in order to lock into the flexible plate.
The small keys can present a choking hazard to small children. After the snap fit
design key removal is very difficult as intended.
• Hard plate pin diameters increased in order to decrease the chance of breaking.
Initial testing showed that the separation of the flexible plate and hard plate had no
pin breakage like V1 Easy Fret.
• The A minor key was revised from ‘Am’ to ‘am’ after being informed it was
incorrect.
• The key colors were varied to allow for easier instruction.