kindiana

(OP here) Primary reason is that you can make a big array with only 2 boards, a small board in the middle and a bunch of long boards around it.

Radial pattern of linear arrays with exponential spacing should also be pretty close to optimal for the distribution of pairwise microphone distances to maximize the gain with a fixed number of microphones.

(OP here) the $700 was for 50 arm boards and 5 hub boards, fully assembled and shipped including all the parts (enough for 2 full arrays, with some spares). $350 @ qty 2 is pretty good, considering just the microphones is ~$100 for each array!

Unfortunately the assembly/DFM didn't work out well, but with some better design and foresight it should be much less work/wiring compared to wiring them manually.

(OP here) tverbeure hit most of the main points, but mostly cost ($2/mic vs $0.5/mic adds up when there are 192 microphones), difficulty of finding things with enough i2s interfaces (even with 16 way daisy chaining, thats still more than most/all things will have). The FPGA/custom hardware was part of the fun as well!

OP here, cool to see so many people are interested in this project! Happy to answer any questions (and I'll go around to reply to any questions already here)

It should use less that 0.5 megawatt, 1920 * 150W (High end server CPU) + 280 * 300W (Nvidia Tesla cards)

Check out Three Body Problem, not really AI but... awesome