We're getting close, folks! In a mere six weeks or so, it will be time to celebrate everyone's favorite holiday: Halloween. From cheeky costumes to haunting decorations, Halloween is the perfect holiday for makers. It gives us all an excuse to exercise our skills and comes with a willing audience. But while costumes are an art unto themselves, the real magic happens when you start integrating electronics. To demonstrate that and to provide some inspiration for your own Halloween projects, Mark Donners built this talking animatronic wizard's hat.
This looks like very much like the Sorting Hat from Harry Potter and the Sorcerer's Stone, but that resemblance is mostly superficial. It would, however, be simple enough for Donners to add the appropriate audio files to make this a one-eyed Sorting Hat. That eye is a full-color OLED screen that shows a moving graphic of an eyeball. There are also two animatronic features: a moving mouth and a twitching eyebrow. The hat followspre-written routines, but the user can activate those using a remote key fob like the kind you use to unlock your car's doors.
An ESP32-based development board controls the eyeball graphics, servo motors, and audio output. It shows the graphics on an SSD1351-driven OLED screen, which is 1.5" with a 128x128 resolution and 16-bit color on each pixel. Standard SG90 micro hobby servos actuate the 3D-printed mouth and eyebrow mechanisms. Audio pumps out through an I2S audio board with a DAC (digital-to-analog converter) and amplifier to a small speaker, with audio clips stored on an SD card. The key fob sends commands to the ESP32 through a receiver module designed for that purpose.
The electronics are straightforward enough, but the hat itself required some crafting skill. Donners built the internal rigid form using a technique similar to papier-mâché. He layered on paper, duct tape, and card stock using a copious amount of brushed-on glue. That gave him the flexibility to sculpt the hat into the desired shape, which looks beaten and worn. He then covered that form in brown fabric that had the right texture and color.
And yes, this hat is wearable — though it is quite large and probably pretty heavy.