T5838 MEMS microphones: Top pick for edge AI apps.

Hashtags: #MEMSmicrophones #edgeAI #T5838 Summery: TDK Corporation has announced that its InvenSense T5838 and T5837 digital PDM microphones, part of the SmartSound family, are the preferred choice for low-power edge AI application processors that perform keyword detection. These MEMS microphones feature an innovative Acoustic Activity Detect (AAD) feature that enables system power savings, prolonging battery life.…

https://webappia.com/t5838-mems-microphones-top-pick-for-edge-ai-apps/

Mico is a USB Microphone Based on a Pi Pico

When [Mahesh Venkitachalam] was experimenting with machine learning for audio applications on a Raspberry Pi, he found himself looking for a simple USB microphone. A cheap one was easy to find, but the sound quality and directionality left much to be desired. A large, studio-quality mic would be overkill, so [Mahesh] decided to simply build exactly what was needed: a compact, yet high-quality USB microphone that he called Mico.

The sensing device is a MEMS microphone that outputs a pulse density modulated (PDM) signal. There are chips available to directly interface such a microphone to a USB port, but [Mahesh] found them difficult to work with and therefore settled on something he knew already: the Raspberry Pi Pico platform. Luckily, someone had already figured out how to read out a microphone and present a USB device to a PC, so all that was needed was to put all the bits together into a convenient form factor.

The great thing about the Pico platform is that its main controller chip, the RP2040, is available as a separate component. [Mahesh] designed a sleek little PCB that holds the RP2040 along with the MEMS microphone and a USB connector. The end result looks tidy enough that it might have come out of a mass-produced gizmo. Those don't usually come with full schematics and source code, but the Mico does: everything is available on its GitHub page for anyone to re-use and improve.

You can judge the sound quality for yourself in the video embedded below. If you like DIY USB microphones, you're in luck: we've featured one based on an STM32 as well as a beautiful recreation of a studio-quality mic.

#digitalaudiohacks #microcontrollers #memsmicrophones #raspberrypipico #rp2040 #usbmicrophone

DIY USB Microphone Seems Overkill; Is Surprisingly In-Depth

Those of us who have been working from home through video calls for the past year can attest to the rising demand for conferencing gear such as webcams and microphones. Not wanting to spring for a boring off-the-shelf solution, serial hacker [Andy Brown] decided to design his own USB solution from scratch and show us the process from start to finish.

Deciding to go for a full digital design for the circuitry, the peripheral is based off of a MEMS microphone and an STM32 microcontroller doing the heavy lifting between it and a USB connection. [Andy] notes that MEMS microphones are very delicate and you have to design the PCB around the hole where the sound enters, which is why he went with a breakout board which has the component already soldered onto it.

As for the MCU, he reasons that since this is a off-one project which won't be produced in large numbers, the 180 MHz ARM core shouldn't be seen as overkill, since it also gives him more than plenty of headroom to do signal processing to make the sound clearer before sending it through to a computer by the USB audio device descriptor.

Once the components are chosen and the board designed, [Andy] goes into detail explaining the firmware he wrote for the STM32 to translate the PCM samples from the microphone's I²S interface into a format better suited for the computer. He also describes how it then processes the audio, applying a graphic equalizer to reduce noise and then ST's own Smart Volume Control filter, which works more like a compressor than a simple amplitude multiplication.

Finally, all files for the project, including board gerbers and the STM32 firmware are available at the bottom of his post, and to boot, a video demonstrating the project which you can check here after the break. [Andy]'s choice of microcontroller for this project is no surprise to us, given he's already made his own development board for the STM32 G0 series. But if this digital microphone project is a bit too modern for you, why not try your hand at building a ribbon microphone instead?

#digitalaudiohacks #digitalmicrophone #diy #memsmicrophones #microphone #stm32 #stm32f4 #workfromhome