David McDaid's Rube Goldberg

Aug 23, 2023

Electronics engineer David McDaid has found an unusual use for an empty gin bottle: part of the driving mechanism for a marble-run kinetic art piece inspired by the machines of Rube Goldberg.

"Drawing inspiration from Rube Goldberg machines, I mixed together some electromechanics and art in a [homage] to a personal favorite bottle of gin, by the Isle of Harris Distillery," McDaid writes of the project's origins. "The project took around ~3 months of spare time, includes around ~200 individual 3D printed parts, and around ~250 screws, nuts & washers."

The two-dimensional marble run was designed in Fusion360, McDaid explains, with a view to being a wall-mountable piece of kinetic art built into an oversized box frame. The vast majority of parts are 3D printed, including the links of a roller chain which brings the marble back to the top after a completed run.

"These turned out to be an absolute pain," McDaid admits. "I wanted to avoid using traditional metal chains (that you can buy from literally anywhere) and instead print my own so that I could a) reduce weight, b) maintain flexibility for designing the ball holder arms, and c) make life easier if I were to change any sizes down the line."

Elsewhere in the build is a Trinamic TMC2208 "silent" stepper motor driver connected to a NEMA17 stepper motor, chosen to reduce running noise, a number of LEDs, some driven by an infrared sensor which triggers when the ball passes to play a pulsing animation, and four custom circuit boards — all driven by an Elegoo Nano V3.0 Arduino-compatible microcontroller board.

"There’s only so much testing you can do within a CAD environment, which meant there was a lot of “print, test, repeat” required for each individual component for this build," McDaid notes. "Revisions ranged from a version one working first try, right up to a version 15 for some non-cooperative parts… The total amount of filament used during development was around ~2.5kg [around 5.5lbs]. The total required for the final build is only ~0.66kg [around 1.5lbs]."

McDaid's full write-up is available on his blog.