ExCell: High Expansion Ratio Moisture-Responsive Wooden Actuators for DIY Shape-Changing and Deployable Structures

While there has been sustained interest in shape-changing materials and deployable structures, many existing systems require engineering materials, precision fabrication, and computationally modeled kinematics in order to work. Additionally, many rely on external power sources in order to deploy. In light of these factors, we perceive a need for deployable materials that are easy to design, prototype, and deploy, and that can transform themselves in response to environmental stimuli, making them appropriate for ecological applications. In this paper, we present ExCell, a DIY-able system of water-responsive wooden linear actuators for self-actuating deployable structures. We show that ExCell can be used to develop a wide range of geometries, we present a prototyping method that can create accurate models of ExCell structures, and we suggest four possible applications for this system.