LED Jumprope

For the Kinetic to Light assignment, our group wanted to create a mechanism that would be playful while also allowing for participation from mulitple users. Naturally, we gravitated towards all the playground acitivites. We thought about using swings, but realized the challenge in converting motion in two directions into a stable source of electricity. The next thought was to get a lazy susan to create a scaled-down version of a carousel, but this would involved belt drives and building housing for both the motor and “fly wheel” assembly. We also realized we would probably need to get a lower RPM motor than the one we had already sourced. So finally, we decided to try and create electricity using jump rope.

The initial design will include a single motor in the handle of the jump rope, with the rope attached to the shaft of the motor. If possible, we would like to use EL wire or LED strands as the jump rope itself. Updates to this post will be added here after the next class meeting.

The Build

So the first step in creating our jumprope-powered light involved figuring out a way to attach the rope to the shaft of the motor. We started by cutting a circular piece of wood with a router and circle jig to attach to the motor shaft.


We then aligned a universal hub with the hole from the dowel used in the router jig, since that is the center of the circle. We marked where we needed to drilled pilot holes, took care of that, then attached the hub to the circle.



A small hole was cut from the wheel for the rope to go through, then we attached the motor to the hub using two set screws, and soldered long wires onto the postive and negative terminals of the motor.


We then cut a piece of rope that was approximately 14’ long. Realizing this braided rope would wind itself up if you just gripped onto one end as you spun it, we used a piece of pipe to allow the rope to rotate more freely in one’s hand.

Rope Grip

Here is what both ends of the device look like.

Both Ends

And here is a shot of our simple capacitor and LED circuit.



The bench

Average voltage when using hand crank: 12 - 16V
Average voltage when using rope: 5 - 6V
Max current when using hand crank: 0.1A
Max current when using rope: 0.032A

And here’s the video!

Written on February 6, 2018