Co-investigator V Bove
Project Website http://listentree.media.mit.edu/
ListenTree is an audio-haptic display embedded in the natural environment. Visitors to our installation notice a faint sound emerging from a tree. By resting their heads against the tree, they are able to hear sound through bone conduction. To create this effect, an audio exciter transducer is weatherproofed and attached to the tree's roots, transforming it into a living speaker, channeling audio through its branches, and providing vibrotactile feedback. In one deployment, we used ListenTree to display live sound from an outdoor ecological monitoring sensor network, bringing a faraway wetland into the urban landscape. The intervention is motivated by a need for forms of display that fade into the background, inviting attention rather than requiring it. We consume most digital information through devices that alienate us from our surroundings; ListenTree points to a future where digital information might become enmeshed in material.
A single controller unit is wired to multiple underground transducers, each affixed to the roots of a tree. The controller is designed to be a self-powered, self- contained plug-and-play module, adaptable to any tree. We use a solar panel to charge a battery; computation and wireless network connectivity is delivered by an embedded computer. Audio signals for each tree are generated on the embedded computer and output through a USB sound card and a stereo audio amplifier. Weatherproof connectors on the control module lead to buried speaker cables, which run underground to the transducers. The transducers are cast in silicone rubber to protect them from the elements.