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> Are there any inexpensive microphone arrays? Not that I can find! Building the array is way more expensive than it needs to be. I have limited EE knowledg
by loxias 5y ago
> Are there any inexpensive microphone arrays?
Not that I can find! Building the array is way more expensive than it needs to be.
I have limited EE knowledge, so have been stumbling through it on my own, building my first array out of reference microphones, another with $10 omnis from guitar center, and one with 8x, cheap, repurposed webcams.
Right now, my limiting factor on driving the cost of a future array down is that I haven't figured out how to get a lot (at least 8) I2S inputs to a micro-controller. If that were solved, it would be easier.
- rasz 5y agohttps://www.hackster.io/sandeep-mistry/create-a-usb-microphone-with-the-raspberry-pi-pico-cc9bd5 https://www.hackster.io/sandeep-mistry/create-a-usb-micropho... Main limitation is USB 1.1 IO, so ~1MB/s, unless you are fine with recording to SDcard then probably around 10MB/s. Pico itself can interface 29 microphones with no sweat (30 GPIOs, 2.0 GB/s internal bandwidth).
- loxias 5y agoFunny you should link that! I have gotten as far as getting a raspberry pi zero to be a USB audio gadget, but I haven't played with the Pico yet. The raspi zero has one i2s input and one i2s output. > Pico itself can interface 29 microphones with no sweat. I... had no idea. I thought that since it didn't have an i2s peripheral I was going to have to either find a micro that did, or do something bitbangy using SPI and perhaps an external buffer. I see that it might be possible to get a few I2S inputs using the PIOs. Thanks for this, will certainly give it a shot. (though I don't see how you're getting 29 microphones :P "prove it" ;)
- rasz 5y ago30 GPIOs available to PIO state machines = 29 input pins from PDM MEMs microphones recorder at the same time.