We’ve put together a few drag-and-drop “recipes” for this project that don’t require any programming know-how. More experienced users can see the Customizing page for insights about getting into the code and fine-tuning various details.

Also we’ve created some Halloween-themed cut-out shapes you can use. Of course you can just freehand a design, or there’s tons of freely-available clip art elsewhere on the web…but since these are our own, we can legitimately share them! You can print them out and trace onto cardboard or foam-core, then cut out with a hobby knife…or maybe you have one of those fancy vinyl cutters that also handles construction paper. Use whatever tools and materials you’re comfortable with, it’s all good! When finished, the silhouettes can be taped in a window, or use a hot glue gun to add a “kickstand” in the back, like a photo frame, or a dowel or tomato stake to poke it in the ground.

If designing your own character: the eye holes should be circles about 26 mm in diameter (a smidgen over 1 inch), spaced about 56 mm (2¼") apart center-to-center.

These particular examples do not use the light sensor, since the HalloWing board will most likely be situated just behind an opaque layer of cardboard or similar. But if you poke a hole in your design to keep the light sensor exposed, and if you make the necessary changes to the code, it’s an option. Otherwise the pupils do their own thing.


Plug one HalloWing board into your computer with a USB cable. Make sure the power switch is set to the “on” position, then double-click the RESET button on the back of the board.

After a moment, a small flash drive called HALLOBOOT should appear on your system. Drag-and-drop one of the .UF2 files (downloadable below) on to this flash drive. There will be a few seconds of LED flashing, then the HALLOBOOT drive will be ejected.

Unplug the first HalloWing board and connect the USB cable to the second HalloWing, repeating the process: power switch on, double-click reset, wait for the HALLOBOOT drive and drag-and-drop a .UF2 file there.

With the same software on both boards now…if they’re properly wired and powered on, you should see a pair of blinky eyes!

If it doesn't work:

  • Confirm BOTH boards are switched on.
  • Check your wiring against the diagrams on the prior page.
  • Make sure ONE board has a jumper between A2 and GND.

(The candle effect seen in the animations below is not part of this project…those are separate Circuit Playground Express boards running code from our Jack–o’–Lantern guide.)

Attach HalloWing Boards to Silhouette

Like a Hollywood building façade, nobody’s gonna see this side of things and it’s okay to take short cuts. Line up the eyes with the eye cutouts and hold the boards in place with some masking tape. For something a little more durable, a few dabs of hot glue can work, and is easily removed later using a cotton swab dipped in rubbing alcohol.


A Halloween classic! Two bright yellow eyes with slit pupils. Unlike the original default eye which is a bit too creepy and real, this instead uses a 2D “flat” color, like a cartoon.

The cut-out for this one (PDF file) is a larger design that won’t fit on a single letter-size page…so maybe you can “tile” it across two pages and tape them together.


The other Halloween classic! Again, this one uses a 2D, cartoon-like look, with blue irises in case you’d like to make a Minerva owl rather than a generic Halloween owl.

This one’s a simple one-page PDF. You can dress up the silhouette with a paint pen (as shown above), or cut and glue shapes from colored construction paper or fabric scraps to give it more variety.


Wait, what? Okay, so Naugas have nothing to do with Halloween…but resemble something Tim Burton would stick in his films.

The Nauga is a mythical species from the 1960s that served as a mascot for Uniroyal’s Naugahyde material (a brand of artificial leather).

Simplest eyes of all…white with round black pupil, no iris. Just like the original Nauga.

Another one-page PDF. This might be just a tiny bit too wide for some printers…the edges of the arms might be clipped off…but it’s very little, and you can just freehand those lines.

As with the owl, this can be dressed up with paint pens, or get all fancy with different-colored paper cutouts, or suitably vintage tacky fabric scraps.


Something a bit more Christmas-themed. Cartoon deer eyes with huge specular highlights:

This guide was first published on Oct 26, 2018. It was last updated on Mar 08, 2024.

This page (Software — Easy Recipes) was last updated on Mar 08, 2024.

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