CONCEPT 1:
Picture a coffee table where a steel ball rolls through a bed of sand and traces spirals on its own. This is Sisyphus, a kinetic sculpture by the artist Bruce Shapiro (Colossal).
The secret sits under the sand. A two-motor robot, the Sisbot, moves a magnet, and the magnet pulls the ball along (Design Milk). One motor swings an arm around the center, and the other slides the magnet along that arm. Shapiro compares it to the two knobs of an Etch A Sketch (Midwest Design).
Each drawing lives in a track file, a list of angle and radius points. The table plays these tracks in playlists, the way a music player plays songs (Sisyphus community).
For this assignment, we chose to research a kinetic drawing machine that moves a steel ball through sand to create patterns. Our main reference is Sisyphus by Bruce Shapiro.
Sisyphus uses a polar system, which combines movement around a centre with movement towards or away from that centre. Together, these movements allow the magnet to reach different points across the circular drawing area. The controller coordinates the motors so the ball follows a programmed path.
I think what makes this interesting is how much of the drawing you get to watch happen. The finished pattern looks cool, but I feel like watching it being made is a big part of why you would want this machine in the first place. And then it draws over the existing drawing again and that’s also what I like about using sand. The previous drawing can still be there while the new one starts forming, and you get this overlap before it’s eventually replaced.
It’s also why this stood out to us and seemed more unique that most other drawing machines. With a pen, we could lift it and move somewhere else. Here, the ball is still touching the sand when it moves across the surface, so that movement also becomes part of the drawing. We would have to plan how the lines connect, including the parts where we’re just trying to get from one place to another.
For actually building something like this, we would need a shallow tray, fine sand, a steel ball and a magnet underneath. Then we need a frame and a mechanism to move the magnet, whether that’s a rotating arm or a belt-driven system.
We also came across Jean-Pierre Hébert’s Ulysse, also referred to as Ulysses. This installation uses a slowly moving ball to draw in sand, with each drawing being replaced by the next. Hébert connects this to impermanence, which makes sense when the material itself allows the drawing to be erased and changed so easily. The work was first presented at SIGGRAPH in 1999.
I like this idea of making a drawing that is so impermanent. Usually we’re trying to preserve the final output but here you would have to take a photo or just let it go.
Concept 2: Soft robotics Tentacle
This project uses strings to control a soft, 3D-printed tentacle. The tentacle consists of many separate segments, which makes it highly flexible and lets it move in a very organic way. The core challenge and interesting bit lies in the logic and the math required to move it the way we intend.
We do not aim to build a precise drawing machine. The tentacle will develop its own way of drawing, and its outputs will reflect its physical limits along with the new constraints we discover as we work on it. A brush attached to the tip of the tentacle will serve as the drawing tool.
The technical setup is simple. Maybe it’s not, IDK. We will 3D print the tentacle and connect its strings to feedback servos. Standard continuous rotation servos lack position feedback and cannot track where they are. Feedback servos keep the continuous rotation and also report their position. This gives us control over the length of each string.