Duration
7 weeks
Year
2023
My Role
Product Design
Fabrication
Artfully representing the loudness of the surrounding environment
Alocasia is an audio reactive mechanical sculpture that responds to the loudness of its surrounding environment; the louder the sound, the more it will open. Inspired by biophilic response to danger, the intent is to demonstrate when an environment is loud to the point of injury in a beautiful way.
The entire geometry and motion was modeled and tested in Rhino and Grasshopper to ensure the appropriate movement and proportions before creating the physical structure. Creating a CAD model was an important base of reference for retrieving all necessary measurements during the fabrication process and for exporting the templates required for the 3D printing and laser cutting that formed the basis of the body.
The base skeleton of the sculpture is constructed using brass rod and tubing, filed then soldered to join into the appropriate geometry. Brass rod posts are press fit into ball bearings to create the rotating joints, with the secondary joint press fit into a laser cut chipboard base that is covered in a laser cut white acrylic plate to form the body. The wings are cut with a CO2 laser from an aluminum sheet, then secured to each arm with screws threaded into plastic bushings which had been drilled and tapped, with each screw acting as a set screw against the brass arm. The stepper motor is secured onto the back of the main body, with the shaft press fit into a 3d printed gear on the front which drives the main gear, acting as a crankshaft to drive the body of the brass skeleton up and down, achieving the opening effect.
Incoming audio is registered on a small condenser microphone, then processed into a readable DC signal by a full wave rectifier. A Teensy 4.1 microcontroller processes the level of this received signal then relays the position that should be assumed by the stepper motor, which determines the "openness" of the sculpture.
A more detailed flow of components can be seen in the simplified wiring diagram below, followed by a picture of the assembled components.
Alocasia was designed to open itself up more the louder the environment it's in, taking a rolling average from a decibel rating over a period of 10 seconds and positioning the stepper motor to the appropriate degree. However, unfortunately before fully completed, the microcontroller and custom motor controller/power board were overvolted due to user error when tuning the voltage regulator. This occurred within 48 hours of the projects presentation and therefore rendered the audio responsiveness unusable. With the motor in place, though, it could still open and close across its cycle.
Once completing the sculpture and powering the motor, it's actually incredibly loud as the motor moves through its steps, causing the entire body and wings to rattle. Going for a more quiet operation, for projects such as these in the future, I would instead go for a high-torque servo motor with a better mounting structure, or a DC motor with highly controlled gearing for even smoother operation.