Stuck indoors during lockdown? Here's something interesting you may want to build - alles, who's designer had this to say about it...
alles is a many-speaker distributed mesh synthesizer that responds to control signals over WiFi. Each synth supports up to 10 additive sine, saw, pulse/square, noise and triangle oscillators, a Karplus-Strong string implementation, and a full FM stage including support for DX7 patches. They're cheap to make ($7 for the microcontroller, $6 for the amplifier, speakers from $0.50 up depending on quality). And very easy to put together with hookup wire or only a few soldering points.
The synthesizers form a mesh and listen to UDP multicast messages. The original idea was to install a bunch of them throughout a space and make a distributed / spatial version of an Alles Machine / AMY additive synthesizer where each speaker represents up to 10 partials, all controlled as a group or individually from a laptop or phone or etc. But you can just treat them as dozens / hundreds of individual synthesizers and do whatever you want with them. It's pretty fun!
If you want to know about the original Alles: The Bell Labs Digital Synthesizer, better known as the Alles Machine or Alice, was an experimental additive synthesizer designed by Harold G. Alles and Douglas Bayer at Bell Labs in 1977-78.
Here's Laurie Spiegel Playing it in 1977