Animated Eyes

We will have a labeled Raspberry Pi or SD card with the Raspbian Lite operating system. This operating system has no Graphical User Interface (GUI). You can still connect an HDMI monitor up using the HDMI port. However, your interaction will be through the Command Line Interface (CLI). Basically a terminal window that takes up the entire screen. After you plug in the raspberry pi you will be presented with a prompt.

• Log in as user pi, with password raspberry
• At the command line type:

• Under “Advanced Options,” select “SSH” and enable it. This lets you log into the system using a terminal program across the network, so you won’t need the keyboard and monitor in the future. In other words you will make the raspberry pi headless.
• You will also need to setup Wifi under the Network menu. You will need to know the SSID and passphrase of the network.
• Run the following at the command line, (This downloads and runs a script which installs all the prerequisite software and does some system configuration. It will ask a few questions along the way…)

The following message will be displayed:

This script installs software for the Adafruit Snake Eyes Bonnet for Raspberry Pi. Steps include:

- Update package index files (apt-get update)

- Install Python libraries: numpy, pi3d, svg.path, python-dev, python-imaging

- Install Adafruit eye code and data in /boot

- Enable SPIO and SPI1 peripherals if needed

- Set HDMI resolution, disable overscan

Run time ~25 minutes. Reboot recquired.

Existing installation, if any, will be overwritten.

Continue? [y/n] y              -just type in y for yes to continue

Select screen type: 

1. OLED(128x128)

2. TFT(128x128)

3. IPS(240x240)

4. HDMI

Select 1-4: 1                  -type in 1 for OLED

Install GPIO-halt utility? [y/n] n                

Install ADC Support? [y/n] n                      

Install USB Ethernet gadget support? (Pi Zero) [y/n] n                 

Reboot NOW? [y/n] y             

If everything looks normal and there are no glitches with the eyes, you can skip this part.

• If the eyes are experiencing glitches (video snow, tearing, dropped frames or weird inverted colors), here’s what to do…
  • Log into the Pi remotely using ssh. Then type the following commands:
    • cd /boot/Pi_Eyes
    • sudo killall fbx2
  • The displays will stop updating. This is normal. Then type:
    • sudo ./fbx2 -o -b 8000000
  • The first argument (-o, -t or -i) sets the display type in use; OLED, TFT or IPS, respectively. Second argument (-b) sets the maximum bitrate for the displays. The higher the bitrate, the smoother the animation…but…there’s a limit to how fast this can go, and it can vary with wire lengths, connections, environment (such as interference from other nearby devices) and even slight manufacturing variances from one display to the next.
  • For OLED displays, the default bitrate is 10000000 (10 MHz). But if there’s trouble, we have to dial these back. Try a lower value, like the 8 MHz or 10 MHz. Watch the output for a minute…does it seem to have stabilized now? If only one of the two displays glitches, you’ll still need to work the speed down until both run reliably. Press Control+C to kill the program and test again with a different bitrate…maybe work down 4 MHz at a time, then up 1 MHz at a time until you find the “sweet spot” between speed and reliability. Once you find it, Control+C again and let’s make the change permanent…
  • Type on the command line:
    • sudo nano /etc/rc.local
  • This opens up a basic editor to edit the rc.local file. A couple lines from the bottom you’ll find this: /boot/Pi_Eyes/fbx2 -o &
  • Change that line to read: /boot/Pi_Eyes/fbx2 -o -b 8000000 & (replace the 8000000 with whatever bitrate you found worked best)
  • Save changes and exit the editor. Then type:
    • sudo reboot
  • After a minute or so the eyes should come up again, glitch-free this time. If not, repeat these steps again, trying a lower bitrate until you find a setting that works reliably.

Customize the Eyes

To customize the look of the eyes you can edit the code or the graphic files. The Adafruit website gives you some basic instructions on editing the graphic files. If you go to /boot/Pi_Eyes you will find several files and folders. The ones we are concerned with are:

• eyes.py
• graphics/dragon-eye.svg
• graphics/dragon-iris.jpg
• graphics/dragon-sclera.png
• graphics/eye.svg
• graphics/iris.jpg
• graphics/sclera.png

Type:

Nano is a basic text editor. Use your arrow keys to navigate to line 81 of the code. Unfortunately Nano does not tell you what line number you're at so you just have to estimate and scroll through the code until you find the lines below.

When you are finished hit CTRL-X to exit nano and type "y" when it asks you to save the file.