Sands Of Time

Introducing my latest work-in-progress: The Sands of Time

This is a project inspired by a piece of articulated artwork by Bruce Shapiro, called “Sisyphus Machine“, described as… “an elaborate kinetic drawing machine that uses magnets to drag rolling steel marbles through a thin layer of sand to create complicated mandala-like patterns”. I found the the patterns to be mesmerizing. I felt I could create something along the same lines to experiment with dynamically changing patterns, and – in keeping with my clock making and fascination with time- that would allow the ephemeral praxis of writing time in the sand….

UPDATE: 9 June 2016: My first sand pattern with “Sands of Time

The software traces a simple helical pattern that traverses the centre of the drawing surface so the final design shows two spirals… Neat huh!

Sands Of Time

Sands Of Time: my first sand drawing.. Here, the ball is making a pair of intersecting spirals.

A new top lip – made of 6 identical sections of alder that I shaped on my CNC machine – captures an acrylic drawing surface that is covered in a thin layer of finely ground sand. The magnetic coupling between the carriage’s magnets and the 12mm steel ball bearing is lower than expected so that the friction of the sand is sometimes too great and the ball loses connection. The gap that separates the magnet from the ball is slightly over 3/8″ – 1/4″ ply (as the top support) and 1/8″ acrylic – and this appears too great to ensure a really strong magnetic coupling. So, rather than redesigning the top to reduce this thickness, I shall try out a spherical rare-earth magnet, rather than the current steel ball bearing.

Here, a small thrust bearing is magnetically coupled to the carriage of the carousel, which is rotating underneath a temporary sheet of acrylic. In the completed design, a thin layer of fine sand will sit atop the acrylic and a ball bearing will be moved through it. Articulation of the carriage and carousel will allow for the tracing of “mandala-like” patterns.

In this clip, the carriage and carousel can be seen operating together under the control of separate stepper motors. The unique design (all mine!) places the carriage servo at the absolute centre of the carousel’s rotation. This geometry allows completely independent motion of the carriage and carousel. In other words, the carousel can rotate freely in any direction while the carriage can traverse the carousel’s diameter, and both can operate completely independently.

Here are some build pictures that illustrate how the design has come together. All of the parts have been designed by me using the CAD tool SketchUp with the CAM extension SketchUCam. All of the smaller parts were fabricated out of HDPE on my own CNC machine while the upper and lower plywood panels were cut using the larger Make613 CNC machine.

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Sands Of Time: showing central carousel gear and stepper drive

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Sands Of Time: showing carriage stepper and pulley mechanism

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Sands Of Time: showing underside of carousel and the carriage

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Sands Of Time: showing carousel stepper and mounting

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Sands Of Time: closeup of central carriage stepper mount

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Sands Of Time: initial geometry of carriage across carousel “lazy susan”

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Sands Of Time: initial carriage mount end cheeks

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Sands Of Time: carriage end cheeks snap into mount

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Sands Of Time: belt tension mount underneath carriage

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Sands Of Time: early version of carousel mount

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Sands Of Time: end cheek showing bearing mount

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Sands Of Time: carriage with 8mm rod bearings

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Sands Of Time: end cheeks and belt bearing

 

At this point, the design which includes an Arduino MEGA, a couple of stepper motor drive modules and some Hall effect sensors, is prototyped on a breadboard. I shall tidy this up shortly and add some lighting that will shine through the sand to illuminate the most recent path of the ball bearing.

There’s lots more to come – I plan to CNC the top plate cheeks and cut a disk of acrylic for the uppermost surface over the next couple of days…

Enjoy!

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