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• Prototype-1 and its internals

  likeablob • 01/02/2022 at 16:59 • 0 comments

  So, here is a prototype-1, made by sacrificing my year-end holidays.  
  I hope it makes some laughs on its finishing which is comparable to 4th-grade-homework-crafts-thing.
  (I admit it's due to 1. my gibberish hands 2. my old Kossel k800 FDM printer. But instead of learning hand crafts and replacing k800 with a new SLA printer, I would try online printing services such as JLCPCB or FusionPCB. HP Jet Fusion 4200 with Nylon PA12? What a tech xxxx.)

  Internally this prototype-1 uses the following components:
  

  • 5.9 inch 1920x1080 LCD (Sharp LS059T1SX01) with HDMI driver
  • Orange Pi Zero plus 2 (H5)
  • 12 bits WS2812B ring
  • Simple cuboid frame made with OpenSCAD (.scad and .stl files are available at https://github.com/likeablob/kagedourou/tree/c5b98a41908b3c6a72b444cdd511a78905feda29/structure)
  • Some sheets of Washi paper

  And here is my work log (for myself);

  • Print the parts of the frame, glue them together.

  • Make the LCD driver piggy-backed on the LCD with double-sided tape. Solder two wires for powering to the driver board.

  • Attach the WS2812 ring on the bottom panel with double-sided tape. (Watch out. It's sticky!)

  • Insert the LCD panels into the frame and screw the bottom panel to the frame tightly.

   
  

  That's it. Then it's time to power the OPi on.  

  • This time I used Armbian 21.08.1 Focal with Linux 5.10.60-sunxi64: https://www.armbian.com/orange-pi-zero-2-h5/
    • Just connect the board to your machine, the board will be detected as a virtual serial device (USB ACM device backed with g_serial).
    • `screen /dev/ttyACM0 115200` and then `sudo armbian-config` to get started.
  •  To bring up X11, just apt get some packages.  Here is a snippet based on my macmini project.

    • $ sudo apt update && apt install -y -q \
          chromium-browser \
          matchbox-window-manager \
          nodm \
          xserver-xorg-input-libinput \
          xserver-xorg-video-fbdev \
          x11-apps \
          xinit \
          xfonts-base \
          xloadimage \
          tmux \
          x11vnc
      
      $ sudo sed -i.orig -e "s/NODM_USER=root/NODM_USER=${USER}/" /etc/default/nodm
      
      $ vi ~/.xinitrc
      #!/usr/bin/env bash
      xterm -e tmux &
      matchbox-window-manager -use_titlebar no
      
      $ chmod +x .xinitrc

  • Install mpv and yt-dlp for streaming YouTube.

    # Install yt-dlp with pipx
    $ sudo apt install -y python3-pip python3-venv mpv
    $ python3 -m pip install pipx
    $ echo 'export PATH=$PATH:~/.local/bin' >> .zshrc
    $ source .zshrc
    $ pipx install yt-dlp
    
    # A workaround for a little bit outdated mpv (v0.32.0-1ubuntu1)
    $ ln -sf ~/.local/bin/yt-dlp ~/.local/bin/youtube-dl
    
    # Bad apple!
    $ export DISPLAY=:0
    $ mpv -fs --panscan=1 www.youtube.com/watch\?v\=on2MUzhuVMw

  • To use the WS2812B ring, use the SPI bus and some Python scripts.

    • # Enable the SPI bus
      $ sudo vi /boot/armbianEnv.txt
      ...
      overlays=gpio-regulator-1.3v spi-spidev usbhost2 usbhost3
      param_spidev_spi_bus=1
      $ sudo reboot now
      $ ls /dev/spidev1.0
      
      # Install the required dependencies
      # You may want to use poetry or pipenv
      $ sudo apt install python3-dev
      $ sudo python3 -m pip install spidev
      $ wget https://raw.githubusercontent.com/likeablob/openvino-opencv-docker/master/demo-face-detection-ws2812/ws2812b.py
      $ vi test.py # See the following snippet
      $ sudo python3 test.py

    • #! /usr/bin/env python3
      from ws2812b import WS2812B
      
      led = WS2812B(12, spi_bus=(1,0))
      led.off()
      
      led.show([[250, 250, 200] for _ in range(12)])

    • Oh, don't forget to wire the ring to the board. WS2812's DIN is connected to OPi's PA15 (SPI1_MOSI).

  • Lessons learned;
    • The WS2812B ring roughly placed at the bottom of the frame lights the thing perfectly.
      • To make it work reliably, I'll need a level shifter. https://hackaday.com/2017/01/20/cheating-at-5v-ws2812-control-to-use-a-3-3v-data-line/?
    • Sometimes the LCD comes off from the frame. It would be better to move the screw holes of the bottom panel slightly to the LCD. 
    • I hope if I could use Markdown in the project log...

  ------ cut here ------

  To draw a dynamic silhouette onto a surface, the following ways are in my mind;

  • A. LCD
    • A-1. Full color LCD with...

  Read more »

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