ReSpeaker has released its 4-Microphone Raspberry Pi HAT (Hardware Attached on Top), a quad-microphone expansion board for Raspberry Pi which has been designed for AI assistant and voice applications.
This board will enable you to build your own voice interaction application, or create your own AI assistant. The board can be used in robotics or in smart homes, IoT scenarios, and conference rooms, and is customisable as you add new modules.
The board has been developed based on AC108, an integrated quad-channel ADC (Analog to Digital Converter) with I2S/TDM (Time Division Multiplexing) output transition which will give a high definition voice capture.
The four microphone version also comes with an LED ring, which will flash in the direction of your voice.
This HAT has four analog microphones and 12 APA 102 programmable RGB LEDs in a ring. When this is connected, the Raspberry Pi will have the ability to do Voice Activity Detection (VAD).
It will also be able to estimate the Direction of Arrival (DOA) of the voice, and show the direction of the voice via the LED ring, in the same way that Amazon Echo or Google Home does. It also has the ability to use keyword recognition.
The board has been developed on the Cirrus Logic WM8960, a low power stereo codec which will provide 1W per channel into 8W loads.
There are two microphones on both sides of the board for detecting sound. There is also a user button and two on-board Grove interfaces for expanding applications.
The Grove system uses a modular, building block approach to building electronics systems with buttons sensors such as motion detectors or heart rate sensors.
The board also has a 3.5mm audio jack or JST 2.0 speaker connector for audio output. It is compatible with and will support Raspberry Pi Zero and Zero W, Raspberry Pi B+, Raspberry Pi 2 B and Raspberry Pi 3 B.