These simple-but-fun string-climbing Makey bots are based on an old folk toy. They climb up strings by using friction and alternating tension/slack. Make two bots and have a race!
Download and print out the parts, and paste them onto a piece of thin plastic or wood, then cut out the robot racers and the swivel shapes on the solid black line.
Drill the holes in the swivels. Tie a short loop of string to each of the top center holes. Tie long pieces of string (4 feet or even longer!) to each of the bottom holes.
Cut four 2½” pieces of plastic drinking straw. Use cyanoacrylate (super glue) to attach 2 straws to the back of each racer. Angle them slightly as shown. Thread the long strings though the straws and tie a bead or dowel at the end as a handle stop.
To race, hang the loops up on a wall on 2 side-by-side nails. Hold the strings apart, one in each hand, and while keeping a light tension on both, gently pull on one string, then the other. With alternating left-right-left-right tugs, the racer will slide up the strings in little jumps. Quick, keep going: first one to the top wins! (But don’t tug too fast; the climber will stall!) Release tension and the climber falls back down, ready for another race.
» Have a race of multiple “laps”: first to complete 10 up-and-back trips wins!
» Team up with partners: one person tugs one string, their partner tugs the other. It’ll take coordinated teamwork to go fast and win!
» If you have a really high space, like over a stairwell or loft, try stringing up the racers with super l-o-n-g strings!)
