We present WallBots- autonomous, wall-crawling robots as a research probe for public expression across a wide range of surfaces and hard-to-reach places, including bus stops, whiteboards, streetpoles, trashcans, moving vehicles and building walls. We evaluate WallBots as a low-cost DIY authoring tool for public artists and activists.

We developed two prototype magnetic robots that we call WallBots. These robots have two wheels with (commercially available) magnetic disks glued around each rim, allowing WallBots to defy gravity. Wheel rims are covered with silicone paste to increase traction as robots traverse vertical surfaces in any direction. A continuous servo motor drives each wheel, as two rechargeable lithium batteries power the robot. WallBots are controlled by an Arduino Mini— an open microcontroller that is widely used in numerous art projects for its flexibility and easy programming (for example, to control Jackoon an artbot that paints on horizontal canvases [49])We printed a custom circuit board to connect and house the electronics, allowing for accessory sensing and expression capabilities, as additional electronics can be attached directly to the board. For instance, our PCB design includes slots for a BlinkM – a powerful pic-controlled tri-colored LED that can be easily programmed for any color, pattern or fade sequence, to express the WallBot through light. The back of the board houses slots for LED’s, which we have implemented as tail lights to playfully indicate WallBot turn direction.

WallBots in the Hands of Public Artists and Activists

Street art and political activism have a rich history of shaping urban landscapes. Our work explores the processes by which public artists and political activists contribute to public spaces, introducing opportunities for HCI researchers to engage with the people who shape the aesthetic feel of our cities.

Our study of six individuals who extensively contribute to public spaces offers insights into the materials and practices behind grassroots public expression. We then leverage feedback from participants, among them a graffiti artist, light painter, political activists, and street musician, to evaluate interaction techniques for manipulating WallBots as a medium for public expression across a range of surfaces. Our findings expose a research space for technological interventions in the context of street art, and we conclude with design insights for magnetic kinetic systems as an approach for supporting engagement, expression and creativity in public spaces.

Interaction Techniques for Manipulating WallBots on Public Surfaces