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• The end of 2019 & the start of 2020

  Yihui • 12/31/2019 at 19:09 • 0 comments

  I started the project from March of 2019. It took much longer time than I expected to make the VOICEN Linear 4 Mic Array. At the end of 2019, the hardware kit is available at Makerfabs. You can also find the hardware design resources including schematics and gerber files at https://github.com/voice-engine/hardware.

  The project is not finished yet. At 2020, I will focus on writing more documents of how to build a smart speaker from scratch. There are some lessons I learned from this project. Hope it will help me do a better job at the next project.

• Make a smart speaker paper case by hand

  Yihui • 11/11/2019 at 04:40 • 0 comments

  Previously, I had a brief introduction of using LibreCAD and Python to design a CAD file for a paper  case. When we get a CAD file, we need a laser cutter o cut a paper case. However, not everyone has access to a laser cutter, so it would be cool if we can make a paper case by hand with our daily tool.

  Tools & Materials

  • scissors
  • knife
  • ruler
  • pencil
  • screwdriver
  • 400g kraft paper
  • double-sided tape

  
  Steps

  1. Draw the outlines of the paper case

  The design is quite simple. It's just a box with a lot of holes for a speaker, 4 microphones, 4 LEDs, 1 screw and 2 rivets. We can get the dimensions from the CAD file, then use the pencil and ruler to draw the outlines.

  I have a laser cutting paper case, so I can use it to draw the outlines.

  We can use the blunt scissors head to re-draw the contours, which makes it easy to  fold the paper to  90° .

  2. Cut the outer frame

  Use the scissors to cut the frame following the outlines. To cut the speaker hole, we can use a similar size bottle cap to help.

  3. drill the small holes for microphones

  It's the most difficult part to do, as we have 4 microphones, 4 LEDs, 1 screw and 2 rivets.

  Drill a hole with a screwdriver.  Part of paper will be extruded. Use a knife to cut the extruded paper.

  To make it easy to drill holes, we can use small puncher from taobao or ebay.

  4. assembling
  

  Use rivets to mount the circuit boards on the paper, and then fix the box with double-sided tape.

  After this process, I made a new design to reduce small holes and avoid using double-sided tape.

  Enjoy the process and have fun!

• Pre-order now! The first 100 pcs will be available at the end of November

  Yihui • 11/04/2019 at 02:50 • 0 comments

  The first hardware kit of the project is coming! You can pre-order it at https://www.makerfabs.com/voicen-linear-4-mic-array-kit.html

  The kit named VOICEN Linear 4 Mic Array lets you build a smart speaker from scratch. It can run a variety of voice assistants such as Amazon Alexa, Google Assistant, MyCroft, Snips Offline Voice Assistant and Baidu DuerOS. It supports AirPlay and UPnP/DLNA. You can turn it into a music box with Mopidy and MPD, or use it to automate your home with Home Assistant.

  Specifications:

  • AllWinner H3 (Quad-Core ARM Cortex A7 @ 1.296 GHz)
  • 512MB RAM
  • 8GB eMMC Flash
  • 16GB Micro SD Card
  • 4 Channels ADC AC108
  • 4 MEMS microphones (64dB SNR, -38dB Sensitivity)
  • 4Ω 3W Loud Speaker
  • 4 LEDs (R, G, B, Y)
  • 1 Touch Key
  • 1 Paper Case
  • 1 Micro USB Cable

  Applications:

  • Built a smart speaker with multiple voice assistants
  • Make a Wi-Fi speaker with AirPlay and UPnP/DLNA
  • Setup a multi-room audio system
  • Automate your home with Home Automation
  • Learn to use a variety of audio processing algorithms such as AEC, DOA, NS and Beamforming
  • Learn how to send data over audio

• Get started VOICEN OS: hey_wifi + ttyd + jupyterlab = awesome!

  Yihui • 10/10/2019 at 11:24 • 0 comments

  Last time I showed a web app of sending data over sound to setup Wi-Fi. A further step is to integrate it with a web terminal - ttyd and JupyterLab. These web apps are included in VOICEN OS which is based on Armbian OS. Have a look at the video to find out how it works.

  Steps to get started with VOICEN OS:

  1. Press and hold the touch key of the device for 4+ seconds to turn the device into Wi-Fi setup mode

  2. Boardcast WiFi SSID and password through sound on the hey_wifi web app

  3. After the device received the SSID and  password and connected to the Wi-Fi network, it sends its IP address to the web app, and then the web app generates a link which is linked to the device dashboard.

  4. Click the link with the device's IP address, we will get the dashboard of the device.

  5. We can open a web terminal (ttyd) to add a new user. The default user is root. The default password is 1234.

  6. We can also open JupyterLab which is a very powerful web IDE. It allows you to create and share documents that contain live code, equations, visualizations and narrative text. In this document, you can run python or shell scripts to play sound, plot graph and analyze data.
  

  That's it. Do you like it? It would be great if you kindly give me some feedback.

• Send WiFi settings through sound wave

  Yihui • 06/21/2019 at 13:39 • 0 comments

  When we get a smart speaker, the first thing we need to do is to connect it to the WiFi network. There are a lot of ways to setup the WiFi connection, such as SmartConfig, Bluetooth Setup. While we have a cool way to setup the WiFi connection for a smart speaker. As the title says, we can transmit WiFi settings through sound. The smart speaker decodes WiFi settings by analyzing sound, and then connect to the WiFi network.

  The application contains two parts:

  1. web app, based on quiet.js + pure.css

  2. python app on the smart speaker, based on quiet.py

  The code is at https://github.com/voice-engine/wave

• Learn to use blender for 3D modeling

  Yihui • 04/16/2019 at 04:18 • 0 comments

  Last time I used Microsoft's 3D Builder to make a 3D model. The 3D Builder is a handy tool and very easy to learn, but it lacks some functions. So I switched to Blender. 

  Blender is the free and open source 3D creation suite. It supports the entirety of the 3D pipeline—modeling, rigging, animation, simulation, rendering, compositing and motion tracking, even video editing and game creation.

  The story of Blender is very interesting and inspiring (youtu.be/qJEWOTZnFeg).

• Created a simple 3D model for the smart speaker

  Yihui • 04/11/2019 at 11:01 • 0 comments

  We designed a new mic array to build an open source smart speaker, you may wonder what it looks like. So we  created a simple 3D model to show a preview of the smart speaker. The model is created with 3D Builder of Windows 10. You can find the model at https://cdn.hackaday.io/files/1642217026031264/speaker1.3mf

  Top view - 4 R/Y/G/B LEDs, 1 touch pad

  Side view

  Front view

• A presentation of Smart Speaker from Scratch

  Yihui • 04/09/2019 at 05:00 • 0 comments

  This is a presentation of  this project for a hackaday event at Chaihuo Maker Space.  It is worth sharing it here. You can also find the .pptx file at https://cdn.hackaday.io/files/1642217026031264/Smart%20Speaker%20from%20Scratch.pptx

  As an engineer, I always enjoy finding ways to complete a task. For me, the current task is making an open source smart speaker.

  Why we should make an open source smart speaker? What's the to-do-list? How to make it? The presentation is to answer these three questions.

  There are lots of existing smart speakers in the market. They are well-designed products. But they have two common issues. One is that they are always-listening black boxes, which scares many people. The other is that their functions is limited by their vendors. Smart speakers have very powerful ARM processors. They are just like smart phones with touch screens. Smart phones have so many apps, but smart speakers only run one app. Amazon Echo only has Alexa, Google Home only gets Google Assistant. We have no access inside of the smart speakers. We can't install any app on them.

  Maybe we can get some ideas from the history of routers and the OpenWrt project. Before we have OpenWrt, routers were just black boxes. After that, we replace routers' firmware with OpenWrt, and then install a variety of apps, such as web servers, proxies, file storage and etc.

  Maybe we can do the same to a smart speaker.

  But it's a little bit different. Although Amazon released Echo's source code, it's extremely hard to hack a Echo device. For the 2015 and 2016 edition of the Echo, we can boot it from an external SD to hack it. For the latest Echo, it have been fixed.

  For most of us, hacking an existing smart speaker is harder than making a new one. So why not make an open source smart speaker from scratch.

  To find out what we need to do, we should learn how a smart speaker works.

  These can be divided into 3 parts: hardware, software and document.

   
  Hardware is kind of simple. We need a Single-Board-Computer (Raspberry Pi, ...), a mic array and a speaker. Software is the main part. Fortunately, there are lots of open source resources we can use.

  Figure out what we need to do, then we can just find a way to do it.

  The first prototype is made with Raspberry Pi, ReSpeaker 4 Mic Array and a 45mm Speaker. The cost is a little high.

  So next step is to find some more affordable hardware. It seems NanoPi Neo Air is a good choice. It runs Armbian which is based Debian and is very similar with Raspbian.  A new mic array is being designed to reduce the cost.

  Looking forward to your feedback! We can also follow or join the project on hackaday.io or github.

• New design: Linear 4 Mic Array & Amplifier

  Yihui • 03/25/2019 at 15:39 • 0 comments

  The first prototype based on ReSpeaker 4-Mic Linear Array has an issue that its microphones and FPC connector are on top of the PCB. It's not easy to attach the mic array to the case.

  Besides, we want a cheaper, more compact and lower power consumption option.

  So we just designed a new mic array. It works with NanoPi Neo Air, which is cheaper and lower power consumption than Raspberry Pi
  

  The initial thought was like:

  There are 4 microphones, 3 LEDs and 2 mounting holes. The mounting holes are also touch pads which can be used with metal screws as touch buttons. While it was hard to place all the components with this design, so we made some adjustments.

  The new design is:

  There are 4 microphones, 4 LEDs and 2 mounting holes and 1 touch pad + mounting hole.

  You may notice that "VOICEN - Linear 4 Mic Array" is on the PCB, which is the product name.
  

  We got the design work done at March 19th, and sent the gerber files to makerfabs, which provides PCB prototyping service at March 20th.

  Today, we got the PCBs!!!

  Based on the date on the packages, we can find that the PCB manufacturing process was actually super rapid. Its delivery took most of the time.

  Do you like the design or the name "VOICEN - Linear 4 Mic Array"? Just leave a comment here.

• Prototype #1 based on Raspberry Pi + ReSpeaker 4 Mic Linear Array

  Yihui • 03/20/2019 at 14:18 • 0 comments

  This is a paper case smart speaker made with Raspberry Pi and ReSpeaker 4 Mic Linear Array. See also on Github

  Hardware

  The hardware includes:

  • Raspberry Pi 3B (or 3B+)
  • ReSpeaker 4 Mic Linear Array
  • 45mm Speaker
  • Laser-Cut Paper Case
  • + 2 Nylon Rivets (R3035 or R3045), the diameter of mounting holes is 3mm (ф3). Screws will also work, while rivets is easier to use.

  Raspberry Pi and ReSpeaker 4 Mic Linear Array can be found at Seeed Studio, and we get the 45mm speaker and nylon rivets from Alibaba or Taobao.

  Design a Paper Case

  To use a laser cutter, we need a CAD design file. I learned how to use a CAD software at college, but have not used CAD for many years. Fortunately, it is easy to design a paper case. We only have to know how draw lines and circels. Commercial CAD tools are quite expensive, but for this simple task, the open source CAD tool - LibreCAD is enough to get it done. You can design a unique paper case based on my work.

  If you have not used any CAD software, it will take some time to be familiar with a CAD software like LibreCAD. You can also use Python script to genrate the CAD DXF file. Manfred Moitzi's handy Python library - ezdxf will help us to do the design work. For example, to draw an array of speaker holes, using Python script is much easier.

  The Python script is like:

  import ezdxf
  
  dwg = ezdxf.new('R2007')
  msp = dwg.modelspace()
  d = 40.
  n = int(40 / 1.5)
  
  delta = d / n
  
  start = (100, 100)
  
  msp.add_circle(start, 20)
  
  for x in range(-n, n):
      for y in range(-n, n):
          if y & 1:
              offset = 0.5
          else:
              offset = 0
          rx = ((x + offset)**2 + y**2)**0.5
          if rx <= (n/2 + 0.1):
              r = 0.35 # (0.25 * delta * (n/2 - rx) / (n/2) + 0.15 * delta)
              msp.add_circle((start[0] + (x + offset) * delta, start[1] + y * delta), r)
  
  dwg.saveas('speaker_hole.dxf')

   The output will be:

  We can use both LibreCAD and Python script to make a complex design.

  Software

  For a smart speaker, the software is the key point. The easiest way is using Alexa Voice Service or Google Assistant SDK. If you want to know how a voice assistant works, you should try MyCroft. If you prefer to offline voice assistant, Snips.ai is a good option. You can find a full list of resources at voice-engine/make-a-smart-speaker.

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