As the 1mm water streams are interrupted, the light weakens, fingers find delights in the water harp. Echo is silent, until light returns.
I worked with Heena Patel to create the Runaway Harp as the final project for our MA Design for Interactive Media course. The idea of Runaway Harp came from the thinking that an instrument can have her own personality also and therefore wish to express herself in another form. The use of circulating water coincides with our original idea of using Time as a topic for our project, while the actual water interaction was decided from experimentations with water projections.
The Runaway Harp was built from scratch. It was fortunate that we found the appropriately sized tank conveniently abandoned outside our workshop. The construction underwent several phases of prototyping before reaching its final stage.
Beginning with just PVC tubing and 3 pieces of scrap wood losely nailed together, we ended up with an elaborately solid construction which consiste of a wooden box container for the tank, covered by another piece of wood which supports the frame structure, with acrylic sliding .
Acrylic water tube and other strips containing LEDs and LDRs were laser cut with precision such that fingers can be accurately detected. Finally whole construction is glued, primed and painted, and her cover is added on.
On top there are 19 Light Dependent Resistors(N54AY from Maplin), lined up precisely with water streams as well as 19 superbright Leds which are placed at the bottom of the structure. The sensors are connected to Arduino through 3 multiplexers(HC4051 from Maplin/Farnell). The interruption of light beam gives the illusion that touching the water is triggering the sounds of the harp.
After several rounds of experimentation, I found that a combination of using Simple Message System and programming some of the logic in Arduino software was the best solution for communicating the values from multiplexers into Pure Data.
The Arduino program triggers a Midi note in Pure Data when it detects a change in light value between when the finger touches the water and before..
Many thanks to:
Staff from 3D Workshop and Lansdown Centre of Cat Hill, Middlesex University, Maplin, Tinker.it, Lukas Vojir, and Kyle McDonald.