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Can one? Probably. Can I? Never done so before. Can you? :) I know enough EE to do simple things, about the amount you'd expect someone who's worked as a

by loxias 5y ago

Can one? Probably. Can I? Never done so before. Can you? :) I know enough EE to do simple things, about the amount you'd expect someone who's worked as a firmware engineer to know. The fact that you're saying "Can't you ... cheap..."? make me think this must be a viable path though. My hands shake too much for anything but the simplest soldering; is there a cheap FPGA board you'd recommend? And getting all the data into the computer... it could easily be ~70Mbps. (16 mics, 192/24) Making a custom USB class could be a mess, I wonder how hard it would be to just dump ethernet.

cozzyd 5y ago
Can I do right now... no but probably could figure it out :). I don't have any specific recommendations for a dev board, though a selection of some cheap dev boards is here: https://www.joelw.id.au/FPGA/CheapFPGADevelopmentBoards https://www.joelw.id.au/FPGA/CheapFPGADevelopmentBoards If you search around on Alibaba you can find some cheap dev boards that appear to have ethernet already (instead of you having to provide an ethernet PHY, which I think takes up something like 18 IOs?). Beware that even though most dev boards have a USB interface for programming it probably doesn't function as a USB for comms (i.e. you'd probably need to provide another USB PHY). Each I2S device probably requires 3 GPIOs. Someone who knows a lot more about this can probably make a much better recommendation. If you do the beamforming on the FPGA then you probably only need to output a lot less data that might be easily done over a simple UART. In the end, designing your own board with the right-size FPGA is probably the right solution, but that's only cheap per-unit in quantity and requires someone who more than sort of knows what they're doing. Though for someone who knows what they're doing it'd be a relatively quick project...
causi 5y ago
Why in the world would you need to sample at rates that high? The quality of the audio is next to irrelevant, you just need amplitude and position.
- cozzyd 5y ago
  Right, it's not like the microphone probably has much of a response above 20 kHz and you can upsample while beamforming anyway .

by loxias 5y ago

cozzyd 5y ago

Can I do right now... no but probably could figure it out :). I don't have any specific recommendations for a dev board, though a selection of some cheap dev boards is here: https://www.joelw.id.au/FPGA/CheapFPGADevelopmentBoards https://www.joelw.id.au/FPGA/CheapFPGADevelopmentBoards If you search around on Alibaba you can find some cheap dev boards that appear to have ethernet already (instead of you having to provide an ethernet PHY, which I think takes up something like 18 IOs?). Beware that even though most dev boards have a USB interface for programming it probably doesn't function as a USB for comms (i.e. you'd probably need to provide another USB PHY). Each I2S device probably requires 3 GPIOs. Someone who knows a lot more about this can probably make a much better recommendation. If you do the beamforming on the FPGA then you probably only need to output a lot less data that might be easily done over a simple UART. In the end, designing your own board with the right-size FPGA is probably the right solution, but that's only cheap per-unit in quantity and requires someone who more than sort of knows what they're doing. Though for someone who knows what they're doing it'd be a relatively quick project...

causi 5y ago

Why in the world would you need to sample at rates that high? The quality of the audio is next to irrelevant, you just need amplitude and position.

cozzyd 5y ago
Right, it's not like the microphone probably has much of a response above 20 kHz and you can upsample while beamforming anyway .