Mic McCloud – A Cloud Microphone | Wizworks
Summary
I wanted to build a super sensitive microphone to pickup sounds and transmit them via my cloud streaming server so that I could monitor an area remotely. The project goals were: • had to be inexpensive, compared to commercially available “off the shelf” offerings • had to use existing open source components (software/hardware) • had to be sensitive enough to pickup sounds from adjacent rooms • had to be wireless • had to use an efficient sound codec to transmit picked up audio • had to be easy to operate • Raspberry Pi Zero 2W (any small ARM board should work, but it’s got to have wifi) $15 • 32GB MicroSD card – you can use smaller, but this is what I had on hand $8 • 5V wall wart – I had these on hand, but you should be able to source for about $5 The mic element is held in place by a bead of super glue around the edge. I built two units, so what is shown are two Raspberry Pi Zero 2W and two INMP441 MEMS elements: For software, I wanted to keep things simple: no GUIs, no top heavy libraries or applications, just bare Linux, minimal ALSA config, I2S driver, and one of my favorite audio tools: liquidsoap. We can now go ahead and setup the I2S driver: Last, we create a very simple ALSA config file: At this point, your Pi is ready to support I2S sound input. To define your mic’s liquidsoap stream output create a file in “pi”s home directory with the following content: ****** AT THIS POINT: GO AHEAD AND PUT THE SD CARD INTO YOUR PI ZERO W ****** Once you have this file set, you can test your install by doing: If all is good, you should see the stream start.