Kinetic Sand Table

The Kinetic Sand Table is a project that I worked on at home and in my high school engineering course before and during COVID. It has a Raspberry Pi CNC controlled arm mechanism to move the magnetic ball bearing to create intricate designs on the surface of the sand. It is also constructed out of laser-cut legs, and hand-milled pieces of wood that I assembled and stained in my garage.

Sand Table

Please also check out my Instructables documentation page on this Sand Table project. I also have presented this project in the Empire State Maker Faire on the Make: Projects website.

"Branched" drawing

Here is an example of a design that I drew with my Sand Table from a generated THR file (theta, rho).

"Hearts" drawing

The Sand Table is able to draw a large spiral that flattens the sand, preparing it for other designs to be drawn on top of it.

Early build stage

Here is an early stage of the Sand Table physical structure. There are two pins just above the metal arm that I am using as a reference to perfectly balance the arm.

Hardware testing

I am testing the LCD display that is showing the progress of the current file being drawn by the arm's stepper motors. I am also tuning the micro-stepping and step delays to optimize the smoothness of the motors.

Multithreading & LEDs

I was testing the multithreading capabilities of the program that I wrote, which used the LED strips with the custom lighting routines and the stepper motors. The challenging part was to split the motion into small samples and then to synchronize the three threads after each coordinate, while maintaining a fluid, simultaneous motion between the linear and rotational motors.

Hand-routing wood

I used a hand-held router drill to mill circular channels into the wooden surfaces so that a long and thin wooden sheet can be inlaid and become the walls of the table's surface. The walls were made using plywood strips bent with a heat-gun and hot steamer to retain its curved shape.

Wood staining

After milling, gluing, and assembling the wood pieces for the top surface, I stained the wood and refinished it with sand paper so that it became smoother.

Wiring

In the picture, I am splitting the power connection to the stepper motor using a relay board (the one that switches on/off the power to the components). This allows me to turn on/off the power to the components within the program running on the Raspberry Pi.

Table 3D model

This is the 3D model of the structure of the Sand Table: the base, laser cut legs, and the hand-milled table top.

Laser cutting

After creating the model of the pieces for the legs, I used my local university's laser cutter to manufacture these parts.

Final product

More videos of the Sand Table can be found on my YouTube channel.

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