Harmonograph|Pendulum Drawing Machine|Kinetic Art

Description

Counterpoise Mk1 | A Desk-mounted Harmonograph: 
A twin elliptical harmonograph that clamps to the front edge of an ordinary desk. Two pendulums hang below it on gimbals; one carries a paper table, the other carries a pen on a balanced arm. You pull them aside, let go, and the machine draws for a short period and then stops. There is no motor and no electronics. Its certainly not without it's flaws, but thats part of the fun, in the remixing! 

What it is! 
A twin elliptical harmonograph that clamps to a desk. Two pendulums hang below the table on gimbals, one carries the pen arm, one carries the paper platter. Each is tuned by sliding its bob up or down its rod. As the two swing and decay, the pen records the difference between them.
What you get is a Lissajous figure with a decaying envelope: a rosette that tightens toward the centre as the energy leaves the system. The mathematics is done by gravity.

Why "Counterpoise"
A counterpoise is a weight that opposes another weight. Both pendulums are doing exactly that and neither is in charge. The drawing is the argument between them.

• What's in the download:
  Printed parts: gimbal rings and trunnions, split collar clamps, yoke bases, bob carriers, the pen arm hinge and sleeve, platter hub, desk clamp assembly (optional!)
  Bambu Studio print profile, tested on a P1S
  Assembly guide! (but you dont really need one) , Bill of Materials.  The assembly guide includes a github link to a parametric generator where one can change some of the parameters of the model, and reexport STL files, or entire plates. 
  
  This is not a fully printed machine! 
  Read this part before you start. A harmonograph needs mass and low friction, and plastic supplies neither. You will also need:
  

• Timber Dowel

• Weights

• Pen

• Paper

• Machine Screws of Various Sizes

And for transparency!  

The geometry, the lmathematics and the parametric tool were worked out in collaboration with an AI model, which I used roughly the way I would collaborate with a "very fast" draughtsman who never tires of being told the tolerance is wrong. The physical iteration,  printing it, and finding the multitude of errors.. and attempting to fix them, were all me!  I find this to be a very efficient way of modelling. I try to make as much as possible parametric, particularly for products like this, with which aesthetics are borne of functionality. 

Post your first plate. I would like to see what ratios people land on. I think you may get better results from longer dowels, to give more pendulum swing! 
Enjoy!