This is derived from the writings of Paul Liu, Specifically: http://hippomath.blogspot.com.au/2011/06/making-your-own-pendulum-wave-machine.html
Still a 'work in progress' but can be seen in action here:
I made the 'bobs' like small pill bottles so weight can be added - that I have yet to do though I do have some lead shot on order. I hope that the shooter will make the bobs swing more accurately and reduce the tendency to crash into one another.
Once I have the weights then I will retime each pendulum again (the centre of gravity will have changed) and do it more precisely which I expect will extend the time that the bobs swing in a coherent manner.
Because this is quite big for 3D printing (approx 550mm wide and 440 mm high) I have used wood for a portion of the construction.
The upper leg that supports the topmost piece of wood I printed 'upright' Utilizing support for the section that supports the wood. The other legs should be layed down out of printing.
Hopefully the way to assemble is clear from the photos.
I mounted the pendulums in batches of five leaving the cover railing a little loose so that the cable could be lengthened or shortened by yanking the appropriate direction.
All plastic to plastic holes are for 3mm screws.
Produced in an Ultimaker with DiamondAge PLA