Halloween Hat – Project update — Anne


This project is organized around the character of the Sorting Hat from the first of the Harry Potter books and movies. The intent of the project is to amuse people and revoke nostalgia for those who read the books.

Progress to Date

Creating the Neopixel array and coding it has taken the bulk of the time this week. There are 58 neopixels in the strip divided among 2 Adafruit 1/4 neopixel rings and 4 neopixel jewels. I’ve been writing the code to address sections of this array as follows:

  1. The two 1/4 rings form the user hat brim downlight effect. These are numbered 0 – 29 in the Arduino Code.
  2. The next two neopixel jewels form the bottom and top light effects in the mouth and are numbered in the Arduino Code as 30-43.
  3. The last two neopixel jewels comprise the eyes and are numbered in the Arduino Code as 44-57.

Once the array was soldered I tested to make sure all the neopixels were lighting and to understand how the light flows from one neopixel cluster to another.

The next step was to isolate the sections of the strand and assign different colours to single these out for later development. In the photo below of a sections’ test, the hat brim is in green, the mouth in blue and purple and the eyes in red:

The neopixel eyes will go inside ping pong balls filled with polyfill:

Separate from the neopixel array, work has also taken place on the pattern for the structure of the face that will also serve as the mount for the electronics. Here is the simple paper model to figure out how to cut and mount the chipboard facial features:

Tinkercad Circuit

Here is the Tinkercad circuit for the lights. I’ve been able to isolate the sections of the neopixel array:

This is currently evolving to include a push button and vibration sensor. (Though testing isn’t working with the vibration sensor and on further thought, this sketch is likely to be refined to replace with three or more pushbuttons in the next iteration.)

Here is the current Arduino sketch: https://www.tinkercad.com/things/1hI6anIb7sV-sorting-hat-3-neopixel-arrays-and-2-triggers-button-and-vibe

Current Parts list

(2) 1/4 round neopixel strips x15 neopixels each

(4) neopixel jewels

(1 – 4) push buttons

(1) medium vibration sensor #18020 (tbd)

(1) currently on Arduino Uno for development

(1) Audio FX board

(1-2) speakers

(2) lipoly batteries

What’s left to do:

  1. finish writing the sketch
  2. solder the Audio FX board and test with .wav files (already collected)
  3. finish soldering and assemble final electronics. If time permits transfer from Uno and onto smaller Arduino board with lipoly batteries.
  4. assemble the hat with the electronics.