Last year, Seeed Studio launched ReSpeaker WiFi Audio / IoT board based on Mediatek MT7688, as well as an optional microphone array board with 7 microphones and 12 LEDs. Later on, they introduced a $10 2-mic array board for Raspberry Pi Zero (W), and today the company has started to take orders for ReSpeaker 4-Mic Array for Raspberry Pi board for $24.50 plus shipping.
Respeaker 4-Mic Array board specifications:
- X-Powers AC108 quad-channel ADC with I2S/TDM output transition
- 4 Microphones
- 2x Grove interfaces (1x I2C, 1x GPIO port using pins 12 & 13)
- 40-pin Raspberry Pi compatible header
- Misc – 12 LEDs (APA102) connected over SPI, GPIO5 enables power
- Dimensions – 65mm x 65mm x 9mm
- Weight – ~20 grams
The board will give Raspberry Pi board the ability to do Voice Activity Detection (VAD) aka “hot word” detection, estimate Direction of Arrival (DoA) and show the direction via the LED ring, just like Amazon Echo or Google Home. I’m using an Orange Pi Zero board with a single microphone with Google Assistant and while it works fine most of the times range is limited to about 5 meters, and “OK Google” detection may be a problem with background noise like music. For example, I’ve found out it may be tricky to turn off the alarm with “OK Google. Stop” while it is ringing. Such board should help.
You’ll find a getting started guide & Google Assistant tutorial on Github, where you can also download the hardware design files (PDF and Eagle), and X-Power AC108 datasheet (currently wrongly? linking to “AC101 user manual”).