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Interactive sidewalk plays music to your shadows

Interactive sidewalk plays music to your shadows

Designed by Montreal studio Daily tous les jours, Mesa Musical Shadows is a public installation that turns the sidewalk of Arizona’s Mesa Arts Center into a super-sized dance pad which reacts to the shadows of passersby with the sounds of singing.

Shadows cast on different tiles trigger different voices, all while singing in harmony. Length of shadow is dependent upon the season, the time of day and the weather; meaning, a visitor may never quite cast the same shadow twice. The sounds themselves also change with the angle of the sun, which makes interacting with the installation a dynamic experience in the morning, midday, evening, and in the middle of the night. As the day turns into night, the tracks shift from upbeat, Pitch Perfect-like acapella to creepier, ominous tones.

Though all the audio originates with recordings of the human voice, a large variety of sounds and moods are created throughout the day. The sounds triggered in the morning are peaceful and ethereal: sustained choral tones that follow your long shadow, singing you into your day. Later, when the sun is hot overhead, and shadows are shorter; the sounds are chopped and frenetic, creating a rhythmic, energetic soundtrack. As the shadows become long again toward sunset, clusters of complementary, interlocking melodies are triggered. Finally, after dark, the sounds harken toward the natural landscape: Insect or bird-like vocal sounds evoking a nocturnal meadow are triggered by users navigating their way through the night.


The system itself consists of sensors that respond to changes in light, which prompt a range of melodic or percussive sounds emitted through speakers embedded in the colorful fabricated tiles. As Creative Applications details, Mesa Musical Shadows is controlled by a MaxMSP patch linking Arduino Mega boards via OSC.

The installation’s 47 sensors are run through six control nodes, comprised of an Arduino Mega, Ethernet shields, and custom connector shields – each of which is protected in a waterproof enclosure, placed underneath the tiling. Each sensor unit has a custom PCB with a light sensor on top and an LED on its bottom, for nighttime illumination and the more sensitive gear (computers, amplifiers, etc.) is all installed in the museum.

If this musical public display seems a bit familiar, that’s because you may recall Daily tous les jours’ earlier project, 21 Swings, which used playground swings to form a giant collective instrument. Read more about the singing sidewalk here, and see it in action below!

(Photos: Daily tous les jours)