Gogh Bike

Gogh Bike is a tangible user interface harnessing the physical affordances of a bicycle for collaborative creative expression. Users paint by pedaling and steering the bicycle, which directs a virtual paintbrush on a projected screen. Gogh Bike is also collaborative: bystanders can select the color the bicyclist paints with by mixing virtual paint in a bucket on the back of the bicycle.

How It Works

Close Up of the Gogh Bike

Gogh Bike is a bicycle mounted on a stationary trainer, with various sensors detecting the rotation of the handlebars and the front wheel’s rotational speed. The bike also detects when the brake is pressed, which signals picking up the paintbrush so that the painter can pedal to a different section of the canvas without leaving a trail. The bike also has a paint can mounted on its back, and the virtual paint gradually runs out as the user pedals. Bystanders can add paint by tipping buckets emitting colored light into the paint bucket on the back of the bicycle, and by doing so, they can also mix colors for the painter. The bucket on the back of the bicycle has row of LEDs wired to reflect both the color of the paint inside the bucket and the amount of paint. As users pour the colored light in, a speaker by the side of the bike emits glugging noises and the indicator on the bucket rises to provide feedback that the pouring has worked.

Process

Gogh Bike was the final project for my Fall 2009 Tangible User Interfaces class. I worked on it with Ryan Greenberg and Ben Cohen. Most tangible user interfaces using bicycles attempt to encourage exercise or to simulate an actual bicycle ride, but we wanted to explore what a bike’s affordances could do with an art project. We began with the idea of painting on the floor with bicycle tracks, much like the 2009 BMW Z4 ad and [city tracking project thingum], then translated the painting to a digital surface so that the resulting paintings could be saved, and out of the practical limitation of having to demonstrate the project in a small space at the end of the semester. We also wanted to play with the idea of collaborative creation, and as the three of us tossed around ideas of the audience being able to throw in wind, or sunshine, or other things affecting the bike ride, we came up with the idea of a paint bucket mounted on the back of the bicycle that collaborators could mix paint in. We added the glugging noise after hooking up the bucket, as we found it difficult to pour the light precisely into the bucket so that the color indicator would detect the correct color. With the glugging noise, there was aural and visual feedback.

Challenges

The three of us had little to no experience in mechanical engineering, and having to troubleshoot hardware along with software issues was a challenge we didn’t have much experience with. For example, our greatest mechanical difficulty was figuring out how to detect the rotation of the bicycle’s front wheel. Our first steering mechanism looked flimsy, but the combination of chopsticks and duct tape proved to have the benefits of flexibility. Although the mechanism held during the first two demonstrations of Gogh Bike, the weak point proved to be the hot glue attaching the potentiometer to the bike handles. For Maker Faire, Ben and I reworked the steering system and used foam to hold the potentiometer to the bottom of the bike, hoping that keeping it out of the user’s way would hold it together longer. It broke after the first day at Maker Faire, but after repairing it overnight, the steering stayed functional through the rest of the fair. Since I worked primarily on the mechanical aspects of the project, my greatest challenges were thinking of creative, affordable solutions to problems such as the steering. Ben provided knowledge of assorted Home Depot things, whereas my strengths lie in adapting materials for unconventional uses.

Assessment

Although users enjoyed painting with Gogh Bike during the Tangible User Interfaces class fair, the kids at Maker Faire loved it and would line up to both bike and to pour and mix paint. The hundred or so kids who used the bike also provided a great deal of stress testing.

Links

• Extended abstract (PDF)
• NBC news clip (YouTube)

K. Joyce Tsai | Comments