Mechatronics / 2026

Interactive Hermann Park Maquette

Built an interactive Miller Outdoor Theatre / Hermann Park hill maquette as an anniversary gift for my girlfriend, with 3D-printed scenery, lighting, audio, OLED messages, rail motion, and button-controlled behavior.

Small white wood gift box with embedded controls, audio, lighting, display, and hidden rail motion.

Role
Fabrication, electronics integration, embedded behavior
Status
Built
Tools
3D printingPaintingSeeed XIAO ESP32-S3 SenseMAX98357A I2S audioMCP23017 GPIO expander28BYJ-48 stepperULN2003 driverSSD1306 OLEDLED lightingGT2 belt railFreeRTOSButton controlsReed switchNFC sticker
Front demo of the anniversary maquette opening and running its lighting, audio, display messages, and rail motion.

Story

I built this as an anniversary present for my girlfriend: a small white wood box that opens into a Miller Outdoor Theatre / Hermann Park hill scene, based on a place that matters to us.

Build

  • Fabricated the white wood box, hinged doors, carved foam hill, static grass, 3D-printed Miller Outdoor Theatre, train, scenery, figures, picnic details, glow-in-the-dark ceiling stars, and printed exterior photos.
  • Built the electronics around a Seeed XIAO ESP32-S3 Sense with microSD MP3 storage, MAX98357A I2S amp, 28 mm speaker, SSD1306 OLED stage display, warm/cool LED channels, six buttons, reed switch, NFC sticker, and MOSFET switching.
  • Built the hidden train motion with a 28BYJ-48 stepper, ULN2003 driver, MCP23017 GPIO expander, GT2 timing belt, 3D-printed pulleys and carriage, M3 guide rod, and neodymium magnet coupling under the lid.
  • Programmed the box so opening the door and pressing buttons controlled lighting modes, songs, OLED Spanish messages, rail motion, and scene activation.

Engineering notes

  • Used the MCP23017 expander to fit the stepper, six buttons, reed switch, OLED, LEDs, SD, and audio around the limited XIAO ESP32-S3 GPIO.
  • Used FreeRTOS tasks to split audio playback, train motion, button polling, lighting fades, and OLED updates so each behavior stayed responsive.
  • Kept the train mechanism hidden inside the terrain by using a GT2 belt carriage and magnet coupling through a thin lid.

Finished piece

  • The finished box opens into a lit theatre scene with music, moving train, OLED messages, buttons, and a personal anniversary story built into the physical model.

Media

Front view of the Miller Outdoor Theatre anniversary maquette
Front view of the finished gift box scene with the theatre, hill, lights, display, and scenery visible.