I was asked to make a kinetic sculpture for a bike appreciation event. The plan was to make a plywood cutout of a human figure, which would be mounted on a bike with the feet affixed to the pedals. This way when the pedals were spun, the figure would move as if it was pedalling.
Unfortunately the event was cancelled when February in Seattle ended up exactly as wet as you might imagine. I had already started building the thing, however, so I really had no choice but to finish it and post it here. It was a moral imperative.
The articulated figure was cut out of 3/4″ plywood. A Google Image search found me a nice paper doll outline to work from. If you have a projector on hand, that would be the easiest way to transfer the outlines. Unfortunately I didn’t, so I just did it by eye. I measured the rough bounding box for each segment and scaled it up by a factor of 9 (chosen to roughly match my own dimensions), then sketched that onto the plywood. I decided to make the head a separate piece, though there was no technical reason for doing so. This let me adjust the angle to keep the head looking directly forward, no matter how the figure ended up being mounted on the bike.
I first started cutting out the segments using a reciprocating saw, but I was unhappy with the quality of the results. It was very hard to get the left and right versions of a segment to match each other. I pulled out an old desktop band saw and used that instead, with far better results. All in all, I used 2 2’x4′ sections of plywood, and that included remaking a couple segments.
The knees, elbows and neck were attached using 5/8″ bolts. That was much beefier hardware than strictly needed, but I felt it was more in scale with the project as a whole. The hip and shoulder joints had to be spaced farther out, to reflect something closer to the width of a human body. I used 1/2″ pipe screwed into flanges which were bolted to each other through the torso piece with 1/4″-20 screws. Short sections of PVC pipe served as spacers, and pipe caps on the far ends held the segments in place.
With the addition of a bike helmet, the figure was done. I tested it on the bike and the pedalling action worked great when spun manually.
We are angry, frustrated, and in pain because of the violence and murder of Black people by the police because of racism. We are in the fight AGAINST RACISM. George Floyd was murdered, his life stolen. The Adafruit teams have specific actions we’ve done, are doing, and will do together as a company and culture. We are asking the Adafruit community to get involved and share what you are doing. The Adafruit teams will not settle for a hash tag, a Tweet, or an icon change. We will work on real change, and that requires real action and real work together. That is what we will do each day, each month, each year – we will hold ourselves accountable and publish our collective efforts, partnerships, activism, donations, openly and publicly. Our blog and social media platforms will be utilized in actionable ways. Join us and the anti-racist efforts working to end police brutality, reform the criminal justice system, and dismantle the many other forms of systemic racism at work in this country, read more @ adafruit.com/blacklivesmatter
Stop breadboarding and soldering – start making immediately! Adafruit’s Circuit Playground is jam-packed with LEDs, sensors, buttons, alligator clip pads and more. Build projects with Circuit Playground in a few minutes with the drag-and-drop MakeCode programming site, learn computer science using the CS Discoveries class on code.org, jump into CircuitPython to learn Python and hardware together, TinyGO, or even use the Arduino IDE. Circuit Playground Express is the newest and best Circuit Playground board, with support for CircuitPython, MakeCode, and Arduino. It has a powerful processor, 10 NeoPixels, mini speaker, InfraRed receive and transmit, two buttons, a switch, 14 alligator clip pads, and lots of sensors: capacitive touch, IR proximity, temperature, light, motion and sound. A whole wide world of electronics and coding is waiting for you, and it fits in the palm of your hand.