The cymatic water tank visualizer takes any sound or data in the form of sound files, and plays them through deep bass "Buttkicker" speakers to vibrate a tank full of water. Different frequencies excite different modes of vibration of the tank and cause different kinds of patterns in the water.
Higher frequencies make a delicate, wispy, spider-web-like pattern on the surface of the water, while lower frequencies make the water jump as the sound creates standing waves.
This instructable shows the steps we went through to build the tank, the frame, and the electronics to run the visualizer.
This project is part of the work of the University of California Santa Cruz's Digital Art and New Media department DANM, OpenLab, and designed and constructed by Sean Pace, Zach Corse, and David Harris.
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Step 1: Building the Water Tank
The water tank is built from acrylic and was made in two stages.
First, we cut the base from a 8'x4' 1/4"-thick acrylic mirrored sheet on a ShopBot CNC mill at TechShop. We covered the underside of the base with masking tape as a protective layer as we knew it would be vibrating against the wooden stand. That tape has shown wear after a while but can easily be replaced.
The sides were made from two long acrylic strips which we used a strip heater and heat gun to make pliable and a form to shape into the correct angles to match the base. We found having three people working on this was essential to manipulate the acrylic. Don't heat the acrylic too much or else you'll get bubbles forming.
The strips were mounted on the sides of the base and glued in place with SciGrip Fast Set clear, medium-bodied solvent cement for acrylics. The ends were joined also with the cement but then covered in rectangles of mirrored glass to cover the joins between the two sides.
With the cement set, we filled the tank with water, found there were a few leaks, and applied more acrylic cement to the gaps. This cement has worked well and stood up to the vibrations allowing us to run the tank for many hours without any cracking or leakage.
Step 2: Building the Frame
The parts were cut out of 3/4" maple veneer plywood sheets on a ShopBot CNC mill at TechShop. Everything was cut from one sheet of 4'x8' plywood.
After checking the pieces fit together, and the holes were sanded back a little to allow the pieces to fit. Then a two layers of varnish (Varathane, varnish and urethane in one) were applied with a light sanding (220 weight sandpaper) in between.
The buttkicker speakers were bolted to the undersides of the end pieces of the frame.
We added the electronics before completing the frame as it was easier to get the amps in place that way.
With the tank on top, physical construction was complete!
Step 3: The Audio Electronics
The audio input to the wave tank runs through a USB pre-amp and then into the main 900W amplifier needed to run the buttkickers.
We also got hold of a KORG midi mixing desk, also USB connected, as an input to drive the audio in one type of operation of the tank.
Step 4: The Programming
You can use any type of audio input but we found it easiest to operate the tank via Max/MSP.
We then operated in a few different modes:
Mode 1: Mixing desk: The controls from the KORG mixing panel were read by Max and then turned into frequencies that corresponded to interesting resonances of the tank, all between 10 and 90 Hz.
Mode 2: Earthquake mode: A Max patch read the US Geological Survey RSS feed of earthquake activity around the world and then set off a period of vibration for every earthquake with the intensity of vibration proportional to the intensity of the earthquake. There are about 5-6 each hour on average.
Mode 3: The 1906 San Francisco earthquake: We found a data set that recreated the seismometer motions that would have been observed during the 1906 SF earthquake. This data was massaged into an appropriate form and then played back as a real-time simulation of the earthquake. This mode was developed during Science Hack Day San Francisco 2015.
Step 5: Final Piece Displayed
Good lighting and an interesting application make for a crowd-pleasing show. The piece has been shown at a handful of art festivals and the California Academy of Sciences NightLife event. People love to play with the mixing desk mode and make their own beats.
We also show a few more videos of the wave tank in action!