Zooids is an open-source open-hardware platform for developing tabletop Swarm User Interfaces, a new class of human-computer interfaces comprised of many autonomous robots that handle both display and interaction. The platform consists of a collection of custom-designed wheeled micro robots, a radio base-station, a highspeed DLP structured light projector for optical tracking, and a software framework for application development and control. All the material can be found at: https://github.com/ShapeLab/SwarmUI