RAK Wireless has launched a new development board powered by Mediatek MT7628A processor running OpenWrt with built-in WiFi and Ethernet connectivity, and audio codec and microphone to support Amazon Alexa voice service. Bluetooth, Zigbee, and Z-wave will also be supported via UART modules.
- Processor – Mediatek MT7628A MIPS24KEc CPU @ up to 580MHz
- System Memory – 128MB DDR2 (64 MB optional)
- Storage – 16 MB flash + micro SD card
- MicroSemi ZL38062 for audio in and out
- MicroSemi ZL38067 to handle “Alexa” keyword
- single or dual digital microphone up to 5 meter range
- Far field voice wake up
- Support for echo cancellation
- 802.11 b/g/n WiFi 2×2 MIMO up to 300 Mbps
- 2x 10/100M Ethernet (LAN and WAN)
- Optional UART modules for Bluetooth, ZigBeem Z-Wave
- USB – 1x USB 2.0 host port
- Expansion – Arduino headers with UART, I2C, SPI and GPIOs
- Power Supply – 5V via power barrel or mini USB port
As you can see from the photo below, the main components are on separate boards (for some reasons) with a “mother board”, MT7628 module, and an audio sub-board.
As mentioned in the introduction, the MT7628 module runs an OS based on OpenWrt with RAK iGate middleware, and the company provides an SDK allowing you to develop solutions based on Amazon Alexa thanks to one codec that will detect “Alexa” keyword and wake up to the board, and another codec handling audio capture and output. The software architecture is shown below, Wiscore app for Android and iOS is provided to pair the EVK with Alexa, and more documentation and software can be found in the Wiki on Github.
The solution can be used to build voice controlled home automation gateways or appliances, smart speakers, and robots. RAK Wireless sells a development kit with the three boards, an Ethernet cable, a speaker, a USB cable, two antennas, some Dupont wires, some jumpers, and a Quick Start Guide for $49 plus shipping. Visit the product page for a few more details.