Our goal for the Finger Symphony was to create an interactive, visually engaging sound machine, approaching a musical instrument. We were inspired by the Intel Animusic Machine (https://www.youtube.com/watch?v=PCIkbr9HCcw) that uses mechanical movement to create an engaging visual and aural experience. We initially wanted to use marble-launching solenoids to hit targets and produce the sound, but refined that to solenoids directly hitting the sound making target for time constraints.
We cut aluminum extrusion pieces that we found in the lab to specific lengths relative to each other to produce six sequential notes (relatively tuned to C, D, E, F, G and A). We hung those in an enclosure made of wood for resonance, and positioned solenoids to strike them and produce the sound. The solenoids are driven by relays, which are driven by a ULN2803 Driver, which is controlled by an Arduino. The Arduino also has 10 input buttons attached, 6 of which allow manual playing of the 6 notes, with a record button and three preset song buttons.
The bars produce a quite pleasant sound, and the solenoids and enclosure are conducive to that. The tuning of the exact motion was difficult, however, because the bars had a tendency to swing and ‘miss’ immediate subsequent strikes. Technical issues with the wiring and detection of the buttons and insufficient time to debug meant that the input buttons were never fully realized, although the code was implemented. In autonomous mode, the solenoids function properly, but the swinging bars provide an inconsistent sound that sounds a bit random, so the programmed songs sound more like ambient wind chimes. The final product is not interactive as we had hoped, but we are satisfied with the visual engagement and sound of the device.
Because of the process issues with the input devices, the video shows the Finger Symphony in autonomous playing mode. https://vimeo.com/148553483
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