R Zach



The Price of Tea in China

A tangible representation of sometimes intangible information about our world (and some nearby heavenly bodies too)

The Price of Tea in China displays data that's gathered from different sources around the web to show the changing relationships, or non-relationships, between: the value of the Euro, the velocity of the solar wind, the temperature of the ocean in Prudhoe Bay, Alaska, the value of of the Dominican Peso, the air pressure on the surface of Mars, and of course the price of tea in China.

As these things rise and fall, small tokens representing them rise and fall as well.

The small red rock representing Martian air pressure. (Actually a brick fragment found on the ground.)

A five-Euro note, representing the value of that currency.

A lasercut sheet of 1/8" yellow acrylic in the form of the Smithsonian Institution's emblem. Representing the velocity of the solar wind.

A small acrylic container of water with a sandy bottom. Representing the temperature of the ocean in Prudhoe Bay, Alaska.

A fifty Peso note, representing the value of the Dominican Peso.

A teabag, representing the price of tea in China. (Or a stock quote from the Ten Ren Tea Co. of Taiwan as a proxy. I know that Taiwan≠China, but I could not find a Chinese tea company whose stock price was listed online.)

All of these data points are available freely on the web. What a strange thing to live in a time when you can find out updated answers to burning questions like "what's the air pressure doing on Mars these days" by fiddling with your hand-sized computer for a few moments!

In case you're wondering, I used the (now somewhat defunct) web service Kimono to pull some of the data from their various sources, funnel through a Processing sketch, and send serial commands via Bluetooth to an Arduino hiding inside the wooden enclosure. (Some data sources were available without any Kimono arm-twisting needed.) Here's a system diagram of the data flow:

Below is an electrical schematic for the system. I used my trusty and very inexpensive friend the A4988 stepper driver once again. As in all the images on my site, just click and hold to see a magnified version (or of course right click and download for the original resolution).

I think this piece begs, implicitly, for the viewer to interpret and interrelate the various data streams shown. Some surprising relationships between disparate data may be actually valid: for instance, high velocity solar winds can impair satellite communication and affect economic variables on Earth. But what might the air pressure on Mars have to do with the price of tea in China? Probably not much. But in a quantumly entangled universe, who can say? ⁂

Arduino and Processing sketches, as well as Fritzing schematic file, available for your enjoyment in priceoftea.zip. (Additional goodies included: DXF cutfile for the reels I made to fit on the 5mm D-shaft NEMA 23 stepper motors I used, and another DXF cutfile of the little water-holding open cube.)
Creative Commons License  2014 Robert Zacharias