This is a pendulum wave that can be printed on the A1 Mini in less than 3 hours. I have included print profiles for the A1 Mini and for X,P and A series printers. I have also included all the stl files and the Fusion design file if you want to  play around with the design. Here is a link to a higher quality 30 second video (GIF is jerky) Mini Pendulum Wave.mp4

Pendulum waves are unique demonstration of the physics of oscillation. The lengths of the pendula are set such that in a given time t, the first pendulum completes x oscillations, and each subsequent one completes one more oscillation than the previous. As all pendula are started together, their relative phases change continuously, but after time t, they come back in sync and the sequence repeats. I designed the lengths of the pendula for a 15 second oscillation period.

This is the formula for pendulum length:

Where:

L= length of the pendulum in meters

T= oscillation period in seconds

g= gravitational acceleration

k= is a constant determined by the first pendulum in the series

n= pendulum number

I created a spreadsheet to determine the length of each pendulum. I set the oscillation time for 15 seconds and the first pendulum length to 150mm (.15m)

I then used Fusion to design a parametric model for the pendulum where I could input the pendulum length from the spreadsheet to create the correct length for each pendulum. I have included the Fusion design file. Use the parameter page to set the length of the pendulum.

Printing Instructions

This is a fairly easy print. I printed in PLA with .4mm nozzle and .2mm layer height. The top shaft is printed at .1mm layer height. You can print even and odd pendula in different colors. At one point during the oscillation you can see the colors line up on either side.

Gather all the parts and use a length of filament to thread the pendula into the top shaft in order of length. Clip the filament at the ends and press the A-frames onto the hexagonal top shaft

To start the oscillation, use the start board to raise all the pendula together while holding the top of the frame. Hold the frame for a few seconds after the oscillation begins until the pendula spread out a little bit so it doesn't tip over.

I hope you enjoy watching it as much as I do.

Thanks for looking, MadMax