We've been a long time fan of linkages, and were initially inspired by how they relate to automata. It always fascinates me that by creating connections to other moving points, you can create incredibly complex series of motions from one source, like in these examples by Keith Newstead and Kitundu. For our Spring Fling event last month, we thought it would be fun to explore using clothespins to activate linkages instead of using a crank mechanism.
Kate and I started our experiments using thin soda box cardboard and clothespins. We added elements like foamies, popsicle sticks, and skewers to make them sturdier and accentuate the relatively small motion of the clothespin opening and closing.
We also experimented with using both different materials (like tongue depressors, straws, thicker cardboard, and paper) and different orientations of how the linkages could be configured (like flat on a table or held vertically).
In the end we settled on medium thickness cardborad strips as our favorite material to work with. We made two different length strips with laser cut holes for experimenting. They can be configured with brads and activated by two clothespins hot glued together. For the spring fling event, I ended up creating some example mechanisms, inspired by the aesthetics of our cardboard automata motion examples.
A few weeks after the spring fling Monika, from the Lawrence Hall of Science, came by the Learning Studio to continue exploring linkages with us. She shared some of the experiments they've been doing using servo motors to activate linkage systems to make animals for a robotic petting zoo.
We were stuper intrigued by that idea and got started right away trying to make our own motorized linkages. Ryan had the idea of using an extra marble machines board we had lying around to be the base for the linkages. I started with a simple mechanism that had a combination of fixed and moving points. I wanted to make it more three dimensional so I added a secondary piece that caused a straw with a piece of string to bend up and down.
Luigi (on the far left in the video below) started with a simple slider mechanism that had an interesting slow/fast movement. He kept adding and experimenting to make a complex shape that transforms between a diamond and a triangle. Ryan (bottom center of the video) pulled out a Lego WeDo motor to activate his mechanism. He programmed it to rotate right and left to make the linkage extend and contract. He also experimented with using pegs to constrain the linkage at different points to see how it affected the motion. Monika (top center of the video) made a linkage that creates amazing slow elliptical patterns.
Monika and I also were interested in experimenting with scale of our linkages. We created a giant "fish mouth" linkage that operates by creating hand holds similar to a pair of scissors. We iterated on the size of the strips we were using since the initial ones were too short. We also realized that it was helpful to have some connection points be fixed, so we hot glued those to keep them in place.
I've really enjoyed experimenting with linkages because there's so much to discover as you play. This summer we'll diving into more ways to explore linkages, starting off with a residency with Noga Elhassid after Maker Faire. We'll keep posting with what we try next!