The purpose of STEVAL-MKI138V1 is to provide a demonstration of decoding and streaming of digital MEMS microphone outputs. The STEVAL-MKI138V1 demonstration board hosts the MP34DT01 (top-port digital microphone), working as a sensor and the STM32F107RC microcontroller, which functions as an audio decoder.

These microphones are analog-to-digital transducers. They are capable of sensing sound pressure and converting it to a digital signal using the PDM technique. The STM32 microcontroller decodes the PDM signals from the microphones and streams the audio via USB.

The STEVAL-MKI138V1 is a sound card automatically recognized by the PC as an audio device. Connection is made through a USB cable, which both powers the board and streams the audio collected from the microphones to the PC. It is also possible to use the STEVAL-MKI138V1 as an interface board for other microphone boards (STEVAL-MKI126Vx), in which case use of the APWorkbench software tool is recommended.

Applications: Mobile terminals, Laptop and notebook computers, Portable media players, VoIP, Speech recognition, A/V eLearning devices, Gaming and virtual reality input devices, Digital still and video cameras, Antitheft systems