HalloWing ships with a pre-loaded example of a human eye that looks around, blinks and reacts to light.

If you want to put the different spooky eyes on your HalloWing, enter bootloader mode by double-clicking the Reset button and then drag the appropriate UF2 file over onto HALLOWBOOT:

The UF2 files for different eyes can be found at this link.

Drag and drop the .UF2 onto the HALLOWBOOT drive on your computer. It will eject automatically (you may get a warning from your computer, you can ignore this). 

Customizing the Spooky Eye Demo

The software controlling HalloWing’s eye is extensively customizable. This requires some familiarity with the Arduino IDE and, depending on the extent of customizations you have in mind, perhaps some image editing and using Python scripts on the command line. Customization, therefore, is more of an intermediate-level project.

This is all explained in the Electronic Animated Eyes  guide

Most of the code there will automatically work on the HalloWing hardware, such as the display and light sensor. Other HalloWing-specific features, such as the capacitive touch pads, are not handled by the code…but could be added if you’ve done some Arduino programming before.