Use an Adafruit HalloWing M0 Express to build this iconic spell book!


We've waited 300 years, right down to the day, now the witch is back
and there's hell to pay!


In this project we'll put a spell on you and use our witchcraft powers to build our very own book.


If you don't believe, you'd better get superstitious.


This is Hallowing..this is Hallowing... Hallowing! Hallowing! Are you the kind of person who doesn't...
Out of Stock
Lithium ion polymer (also known as 'lipo' or 'lipoly') batteries are thin, light and powerful. The output ranges from 4.2V when completely charged to 3.7V. This battery...
In Stock
The eyes have it! Add this little lens to make a big expression with our Spooky Eyes demo for microcontrollers or Raspberry Pi. These are plastic lenses, with brilliant clarity and a...
Out of Stock
The eyes have it! Add this little lens to make a big expression with our Spooky Eyes demo for microcontrollers or Raspberry Pi. These are gorgeous glass (not plastic/acrylic!)...
In Stock
Here is the perfect kit for mounting a convex lens (glass or plastic) to your
In Stock

Prerequisite Guides

If you're new to Adafruit CRICKIT, Circuit Python and soldering, take a moment to walk through the following guides to get you started.


A list of helpful tools used to make this project.

1 x 1 – 3/8in Spade Drill Bit
1 – 3/8 in Spade Drill Bit for Lens opening
1 x Crayola Air Dry Clay
Crayola Air Dry Clay for snakes
1 x Mod Podge Acrylic Sealer - Matte
Mod Podge Acrylic Sealer - Matte to glue and seal parts
1 x 5M Burlap Twine
5M Burlap Twine for the stitches
1 x Tulip Soft Fabric Paint
Tulip Soft Fabric Paint Metalic Paint
1 x Acrylic Paint
Acrylic Paint

Take a moment to review the components in the circuit diagram. This illustration is meant for referencing wired connections - The length of wire, position and size of components are not exact. 

The 350 / 400 or 500mAh Lipo battery plugs directly into the JST battery connector.

You may have to coil the wires to get it to fit between the Feather Wing Sockets. 

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 original spooky eye demo back on your Hallowing, enter bootloader mode by double-clicking the Reset button and then drag this UF2 file over onto HALLOWBOOT:

There’s a few customized variants as well, such as a fiery dragon eye:

A brown, animal-ish eye with no visible sclera:

A psychedelic eye from our Eye of Newt guide:

And a Terminator-inspired robotic eye:

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.

This is all explained in the “Electronic Animated Eyes using Teensy 3.1/3.2” guide (despite the name, it also works on various Adafruit “M0” and “M4” boards as well, including the Hallowing).

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.

Painting book covers


First we'll need to select a large sized cook book that can house our board, lens and battery. Our book measured 8x9.5x2.5 inch (230mmx250mmx65mm).  The pages and cover that will hold the Hallowing in place need to be at least 1.5mm thick. This includes the thickness of the velcro / hook and loop that will attach between the cover and pages.




Next we'll need to sand the covers to make painting easier. We used a 220 grit sand paper and lightly sanded the front and back covers to remove the glossy finish.


Base coat


For the base color, we used a light brown acrylic color to coat the covers. Allow the paint to dry and then apply a darker brown as a texture.



While we allow the paint to dry, we can get started on the snakes! Use air dry clay to mold, shape and texture the three snakes that adorn the front cover.


Eye hole


To create the hole for the Convex Glass Lens, we'll need to use a 1 3/8 inch spade bit to drill out the opening. Use a hobby knife to clean up the edges.


Silver coat


After testing the lenses properly fit through the cover, we can move on to painting the snakes and applying a silver coat to the covers.


Allow the cover and snakes to dry before aligning them to the cover. Check placement and add additional silver coats to the cover and match the design with the snakes on top. 

Stitch detail 


Use the dark brown paint to lightly draw the line details that will make up the stitches. Don't worry if you make a mistake, we can easily dry brush it away to make it into the skin texture.  


Mod Podge pages


After the stitch detail dries we'll move on to gluing the pages that hold the Hallowing board in place. You will need about 1.5mm (about 80 pages) to firmly hold the board. Mod podge each page and then use a binder clip to hold them together while they dry. 

Chipboard backing


After the pages dry, we'll trace out the circle cutout to allow ourselves to center the outline of the Hallowing board on chipboard or card stock. This will help to cover up the mod podged pages. 


Board outline


Next, we'll create an outline of the Hallowing board and trace it onto the mod podged pages. Use a hobby knife to carefully cut out each page.

Test fit cutout


Place strips of velcro around the page boarders and then place the board and Convex Glass Lens on top of the display and carefully close the book cover to test out our tolerances. 


Do not apply pressure to the display, the board or the battery (too much could damage the screen or battery, be careful!). 


Clean up any jagged edges and around the cover to properly fit the parts. 

Glue Backing


After we clean up all edges and test that all of our parts fit, we'll move on to adding mod podge to the backing card stock.


Use a small binder to help keep the pages together while they dry.



On to adding stitches! We'll first prepare the surface by tracing the details with a think layer of mod podge (adds depth). Use a brush to apply mod podge along the lines we drew earlier.   


Now we'll cut about 50 pieces of twine. We'll cut them 20mm long and randomly place them over the glue lines.




Glue Snakes and Lock


We used super to attach the snakes and lock parts into place and sealed with a thick coat of mod podge.


Stitch layer


Once we're happy with the layout we can apply a coat of thick mod podge on top of the twine to keep the fibers clumped together. 


Allow the first mod podge layer to completely dry and then apply a second "skin layer" by applying small clumps in the form of wrinkles. 

Eye lids


To make the eye lids, cut out 1/2 moon shapes until it fits inside your lock (~54mm inner diameter lock).  We'll shape and mod podge the lids to the top and bottom of the inner lock.


Allow the mod podge to fully dry before applying an additional skin layers, like we did before. 

Page details


Print out spell pages and then apply a mixture of light brown paint and mod podge. After it dries, we'll apply textured brush strokes using a darker brown color. We'll try to apply it around the edges to make it appear aged. Use a dry paper towel to apply darker brown for a textured look.


Attach spell pages


To increase the structure of the spell pages, we first glued card stock to the pages in the book and then apply more mod podge the spell pages on top of chipboard. 


We used cards tock that is bigger than the spell page so we can mod podge all of the edges to prevent them from curling. This also covers up uncovered areas (like the original text from the book).

Trim card stock


Once our spell pages are fully dried, we'll go ahead and trim off the excess and cut away at the Convex Glass Lens opening with a sharp hobby knife. 

Velcro / Hook and loop


Now we can stick our velcro / hook and loop that we traced earlier,  to enable easy access to the Hallowing.


Apply to Screen Bezel


The framing around the display is white and will show up when we place the lens on top. Use light brown paint to cover up the white areas. Leaving the protective film over the screen on will help mask it while painting. 

Finishing mod podge coat


Almost there! To create the final skin texture and to lock every thing in place, apply a thick uneven layer of mod podge and allow to dry. 


We allowed ours to completely dry over night, for about five hours. 




And thats it! You can now cast spells on people as they get hypnotized by the eye movements!  

This guide was first published on Sep 24, 2018. It was last updated on Sep 24, 2018.