proposed wiring diagram for the sound system. we use 18 physical amplifier channels, mapped via relays to 108 small speakers.
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The idea is to build a "particle system" or "swarm" with the sound generating system itself, connecting nine Raspberry Pi computers in a network, each contributing with two physical channels and twelve logical channels to the overall sound network.
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Audio Network

30-Jul-2017 - here's a photo from installing the "animal" in situ; we found a great metal frame on top of which the system is installed; it will then be covered by a glass dome. I used a ternary system for the cable numbering, giving an interesting visual pattern of white, black, green, yellow. 04-aug-2017 all channels are setup and working.

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The relay boards have arrived in the meantime. Fingers crossed that all circuits are functional and the design works out as planned…
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prototyping the relay mapping (one input channel and four output channels)
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Found these little beauties at the local electronics store. The left one has a diameter of just 45mm and without further measures has a weaker bass response compared to the right one (68mm). However it has a much cleaner and flatter response, whereas the larger diaphragm sounds quite nasal. There is a reason, the right one costs under 1 EUR compared to 5 EUR for the left speaker.
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23-Jul-2017; almost all parts are here, including threaded standoffs to stack the relay boards and the Pis. Test set-up with one side of a board, i.e. 1 to 6 channels; working fine (see video).
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Once you add a boundary layer to the small speaker, the acoustic bass response becomes quite good. What are we going to do? I think there will be 25cm impermeable discs around them…?

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meta: true
author: HHR
project: SchwaermenVernetzen

keywords: [dynamical systems, swarming, networking, biology, systems, organisms, text, visual, elements, sound, interdisciplinary, particle system, generative system, raspberry, multichannel, network]

"Charlieplexing is a technique for driving a ∞ in which relatively few I/O pins on a ∞ are used to drive an array of ∞."

{kind: note, keywords: [multiplexing, charlieplexing, pins, raspberry]}