That's right, even though the monster eyes firmware is written in Arduino, it still takes advantage of CircuitPython. The eyeball graphics are stored on the CIRCUITPY drive, which is then accessible to the Arduino firmware.

The steps below are a general overview of how to install CircuitPython. If you need more detailed instructions for your specific board, find your board's main Learn Guide on the Learn System and follow along with its Install CircuitPython page.

Find Your Board

After downloading the file, you'll need to put your board into bootloader mode to load CircuitPython.

• On RP2 boards (RP2040, RP2350), you'll hold down the BOOT button, press the RESET button and then release the BOOT button.
• On Espressif boards (ESP32-S3, ESP32-S2, etc), you'll double tap the RESET button.

The drive will disappear and a new disk drive called CIRCUITPY will appear.

Troubleshooting

If you run into issues following these instructions, look for your board's Learn Guide on the Adafruit Learning System. Each board has a dedicating Install CircuitPython page that will go through all of the idiosyncrasies that could come up with your specific board.