ReSpeaker 4-Mic Array: https://www.sparkfun.com/products/14645
Getting Started Guide: http://wiki.seeedstudio.com/ReSpeaker_4_Mic_Array_for_Raspberry_Pi
The ReSpeaker 4-Mic Array is a microphone array for the Raspberry Pi used for voice activity detection (VAD) and estimating direction of arrival (DOA). These can be very handy if you plan to construct your own voice assistant using a Raspberry Pi. Provided demo code can be used to connect to Amazon Voice Service and Google Assistant to allow you to create your own DIY Amazon Echo or Google Home.