Design Studio: Advanced Interactions (MIT Course #: 4.043)
Feb - May 2017
Interactive Standing Wave
Human-Centered Design, User Experience/Feedback/Testing, Interaction Design, Electronics, 3D printing, Craftsmanship, Prototype to a deployable interactive experience, Study history and principles of human-computer interaction, Techniques for rapid-behavior prototyping
Tension Spring, Potentiometer, 12V DC Motor, Wood, Wood Glue, White Paint, Arduino, LEDs, Power Source (x2), Hot Glue
The Interactive Standing Wave is a educational, interactive device that teaches through tactile learning. By minimizing number of buttons and controls, the idea to use touch is enhanced to create a kinesthetic learning experience to understand resonance.
The spring spins since it is controlled by a DC motor, and the user reaches inside the box to creates a loop with their thumb and pointer finger and stops the spring at any location of their choosing. As a result, the spring creates a different number of waves depending on where the user moves their hand.
The inspiration behind The Interactive Standing Wave exhibit is based on the science experiment of standing waves and resonance. I was inspired by how simple manipulation of a string can form mesmerizing and elegant patterns and how simple scientific laws can bring a new and deeper meaning to art and user interaction.
Standing waves are formed from two or more traveling waves that collide and are "in-tune" with one another in such a way that their amplitudes add or subtract in repetitive ways. This is called resonance.
By holding down a specific part of the string, the result can create different harmonics as shown by the diagram below. these are the underlying physics laws that I used for this interactive exhibit.
During the brainstorming phase, I was fascinated with resonance and thought about different ways to approach the topic through an interactive experience. Below are several sketches of different ideas I had at the beginning.
First, I created a proof-of-concept prototype to ensure the success of my final prototype. My first prototype was made out of cardboard and included an a 12V DC motor which I used in the final prototype. I also used a tension spring and 3D printed a DC motor case for the motor to sit in. The tension spring was connected to the DC motor with a part I CAD-ed and 3D printed. Below is the proof-of-concept prototype that also helped me get a better idea of what dimensions I should use to build the enclosure. The enclosure 3 ft x 1 ft x 1 ft. I built the enclosure to be pretty tall to make it feel inviting and interactive for the user.
As mentioned before the electronics are hidden underneath. There are a total of 80 LEDs (4 stripes of 20 LEDs in a line and connected in parallel and powered but an outside power source. The 12V DC Motor is also powered by an outside power source. I coded my project in Processing (flexible software sketchbook and a language for learning how to code within the context of the visual arts) to control the pace the LEDs were pulsing. An acrylic sheet was also laser cut to act as a diffuser to make the light from the LEDs softer.
Upper Enclosure - where user interacts with tension spring
Lower Enclosure - where electronics
DC Motor Case
12V DC Motor
for Diffusing LEDs
The final prototype was made out of 0.125" wood and the shapes were laser cut and glued together with wood glue. The enclosure is hidden in the lower part of the enclosure to keep the Interactive Standing Wave exhibit clean and simple to not create any distractions for the user. The side panels are also curved to create movement that mirror the waves.
There was lots of information that I received from user testing that allowed me to think about future improvements for this exhibit.
Many loved the interactive, kinesthetic aspect of the exhibit, but found the sound of the tension spring hitting the wooden frame to be frightening. Also at first, many users were scared/intimidated to reach their hands inside to grab the spring to pick a place to stop the spring. Future iterations would consider putting a tool inside the exhibit for the user to use instead of their hands.
The purpose of the LEDs were to create a strobe effect, so that the user can "slow down" the image wave formation that the tension spring made, but after a closer look at how strobes work, further improvement must be done to change the locations of the LEDs. Users, however, were very satisfied by the light the LEDs and acrylic plastic diffuser provided.