How do we decide between soil spraying and watering?
Computationally, the surface is divided into 17 tiles. Each visitor’s drawing is translated and rotated to fit one of these tiles. A managing script (the Manager) runs in the background and decides which tile to use next. The Manager tracks which tiles have recently been sprayed, which are still empty, and which require watering. Soil spraying happens during interaction periods, while watering follows a separate maintenance cycle linked to the time of day and the material's condition.
What happens during the interaction and maintenance cycle?
During the interaction period, the system continuously watches for new drawings. When a visitor creates a drawing and the robot is available, the system assigns the drawing to a tile that has not been sprayed recently. The line is converted into a robotic toolpath that accounts for the robot's reachability and is then executed automatically. The robot sprays the soil mixture along the path the visitor drew. If the system detects no new drawing for some time, it can replay an earlier path instead. During maintenance periods, visitor detection is paused, and the robot works through stored paths autonomously. Soil spraying and watering are coordinated independently, allowing the system to maintain the material and vegetation while preparing the surface for the next interaction cycle.
What are we spraying? The robot sprays a living material mixture. It consists mainly of water, combined with clay, soil, psyllium husk, cellulose, and seeds. The plants growing on the surface include grass, chia, alfalfa, and radish.