The first of its kind! A compact variation of the classic trundle wheel, designed for use by the visually-impaired. Small enough to fit in your pocket! The wheel makes contact with a clicking mechanism as it is rolled, generating a click every quarter inch. Surprisingly accurate! Each half of the fork also includes metric and standard measurements (1/8 in and 1 cm), as indicated by the braille markings on each side. The pencil topper functions as a stencil for braille letters. The tool can be used to hold up to 7 pencils!

Parametrically designed with JSCAD! Both standard and metric sized wheels can be generated with any number of subdivisions. Will upload source files when contest ends.

/* UPDATE*/
Adjusted tolerances for optimal assembly. New finalized design (R1) and demonstration video uploaded.

http://youtu.be/79w6xPiDFrA

Just print and assemble! No bearings needed.