Crown Display Thing

Crown Display Thing is an ESP32-C3 driven LED crown display with a built-in web UI, rotary encoder control, scoreboard mode, scrolling marquee mode, and a geared 28BYJ-48 motor output.

This repository is the current firmware source for the project. The firmware already supports:

• WS2812B LED control with multiple display modes
• a browser-based control panel over Wi-Fi
• AP + STA networking at the same time
• live UI updates over WebSocket
• rotary encoder control
• persistent settings in NVS
• OTA firmware updates using a .bin file

Current firmware version: v0.3.0

Included firmware file in this repository:

• Crown_Display_Thing_v_0_3_0.bin
• SHA-256: 8120d427afe6a09cabe014b14a5fc73175a4386ebd728b4241a0536113006fed

Features

• LED modes:
  • Classic Rainbow
  • World Rainbow
  • Full Rainbow
  • Solid Color
  • Marquee
  • Scoreboard
• 7 default display sections, each with:
  • adjustable start position
  • single/double-row layout
  • per-section hue correction
  • per-section scoreboard trim
• 7 editable solid-color presets
• 7 scoreboard players with:
  • custom names
  • enable/disable toggle
  • point tracking
  • winner detection
  • adjustable points-to-win
• marquee text editor with LED exclusion controls
• motor speed control with signed output RPM
• OTA update page in the web interface

Hardware Summary

The firmware is currently configured for:

• controller: ESP32-C3 Super Mini
• LEDs: WS2812B
• default LED count: 200
• rotary encoder: KY-040 style encoder with push button
• motor: 28BYJ-48
• motor driver: ULN2003
• default section count: 7

Pinout

ESP32-C3 Super Mini

Function	GPIO
WS2812B data	GPIO3
Encoder CLK	GPIO0
Encoder DT	GPIO1
Encoder switch	GPIO20
ULN2003 IN1	GPIO5
ULN2003 IN2	GPIO6
ULN2003 IN3	GPIO7
ULN2003 IN4	GPIO4

Wiring Notes

• Connect ESP32 GND, LED GND, and ULN2003 GND together.
• Feed the WS2812B strip from a proper 5V supply. Do not power a full strip through the ESP32 board.
• Power the 28BYJ-48 motor from the ULN2003 board as intended, normally from 5V.
• The encoder uses INPUT_PULLUP, so wire it as a normal KY-040 module with common ground.
• A level shifter on the LED data line is optional but recommended for long wires or noisy power layouts.

BOM

The exact mechanical parts depend on your printed model, but the electronics BOM for the current firmware is:

Qty	Part	Notes
1	ESP32-C3 Super Mini	Main controller
1	WS2812B LED strip	Default firmware assumes 200 LEDs total
1	28BYJ-48 stepper motor	Geared stepper used for crown motion
1	ULN2003 driver board	Driver for the 28BYJ-48
1	KY-040 rotary encoder module	With push button
1	5V power supply	Size this for your LED count and motor load
1	Main power switch	Optional but recommended
1	USB cable for first flash	ESP32-C3 programming
1	Hookup wire set	For power and signals
1	JST, screw terminals, or similar connectors	Optional, but useful for serviceability
1	Large capacitor across LED power	Recommended for WS2812B stability
1	Series resistor on LED data line	Recommended, typically 330-470 ohm

If you publish on Makerworld, add your printed parts, fasteners, brackets, diffusers, gears, and enclosure hardware to the Makerworld BOM beside this electronics list.

Motor Configuration

The code is currently tuned for:

• motor type: 28BYJ-48
• drive sequence: 4-state wave/full-step
• motor steps per motor revolution: 2048
• external gear ratio in code:
  • pinion: 15
  • driven gear: 90

The web UI shows motor speed as output RPM after that external gear reduction.

If your printed gearing is different, update these constants in 00_Config.ino:

• MOTOR_PINION_TEETH
• MOTOR_DRIVEN_TEETH

What You Need To Tune After Assembly

This firmware is meant to be calibrated to the physical build from the web UI.

Expect to set:

• the real LED count if you are not using 200 LEDs
• the 7 section start points
• which sections are single-row led's or double-row
• per-section hue offsets (optional)
• scoreboard trim values
• marquee excluded LEDs if some pixels should stay dark

Default section starts are evenly spread across the total LED count on first boot. For a finished build, you will almost certainly want to fine-tune them.

Controls

Web UI

The device hosts a control page with these main areas:

• LED
• Motor
• Scoreboard
• Marquee
• Advanced Options
• System Settings

The advanced panel includes:

• LED count save + reboot
• section start editing
• single/double layout toggles
• hue adjustment
• scoreboard trim adjustment
• section preview
• marquee LED exclusion tools

The system panel includes:

• Wi-Fi SSID and password
• hostname
• OTA firmware update

Rotary Encoder

The encoder cycles between 4 control modes:

1. Rainbow
2. Scoreboard
3. Marquee
4. Motor Control

Current behavior:

• rotate:
  • rainbow or marquee: change LED speed
  • solid color mode: cycle color presets
  • scoreboard: select enabled player
  • motor: change motor speed
• single click:
  • rainbow: cycle LED style
  • scoreboard: add 1 point
• double click:
  • rainbow: toggle LED axis
  • scoreboard: subtract 1 point
• triple click:
  • scoreboard: reset scores when there is a winner
• long press:
  • cycle encoder target mode

Networking

The device always starts its own Wi-Fi access point:

• SSID: Crown Display Thing
• password: thingsfromthom

If you store local Wi-Fi credentials, it also connects in AP+STA mode so both remain available.

Default hostname:

• crown-display-thing

Web services:

• HTTP UI: http://<device-ip>/
• WebSocket state sync: ws://<device-ip>:81

Build Instructions

1. Install Arduino Dependencies

You need:

• Arduino IDE or arduino-cli
• esp32 board package
• libraries used by the sketch:
  • FastLED
  • WebSocketsServer from arduinoWebSockets

Core libraries such as WiFi, WebServer, Preferences, ESPmDNS, and Update come from the ESP32 board package.

2. Select the Board

Build for:

• FQBN: esp32:esp32:esp32c3

3. First Flash Over USB

With arduino-cli:

arduino-cli compile --fqbn esp32:esp32:esp32c3 .
arduino-cli upload --fqbn esp32:esp32:esp32c3 --port <your-port> .

If you use Arduino IDE, open Crown_Thing.ino, select the ESP32-C3 board target, then upload normally.

4. Join the Device Wi-Fi

After flashing:

1. Power the build.
2. Join the Crown Display Thing Wi-Fi network.
3. Open http://192.168.4.1/ if your device stays in AP-only mode.
4. If STA credentials were already configured and it joined your local network, use the shown IP address or the hostname.

5. Configure The Build

From the web UI:

1. Set the correct LED count and reboot.
2. Adjust the section boundaries to match the physical crown layout.
3. Toggle single/double sections where needed.
4. Tune hue offsets and scoreboard trim.
5. Set player names, marquee text, and Wi-Fi credentials.
6. Save settings.

OTA Firmware Update

Once the device is online, future updates can be done from the browser:

1. Build a new .bin.
2. Open the device web UI.
3. Go to System Settings.
4. Select the firmware file.
5. Start Update & Reboot.

Included Prebuilt Firmware

For easy sharing, this repository already includes:

• Crown_Display_Thing_v_0_3_0.bin

This file was freshly built from the current source in this repository for:

• board target: esp32:esp32:esp32c3
• firmware version: v0.3.0
• SHA-256: 8120d427afe6a09cabe014b14a5fc73175a4386ebd728b4241a0536113006fed

You can upload that file directly from the firmware update page on the device.

If you make further firmware changes, rebuild the .bin before publishing so the shared binary matches the checked-in source.

Exporting A Firmware .bin

To export a binary for OTA upload:

arduino-cli compile --fqbn esp32:esp32:esp32c3 --build-path /tmp/crown_build --export-binaries .

Main output:

• /tmp/crown_build/Crown_Thing.ino.bin

Example versioned copy:

cp /tmp/crown_build/Crown_Thing.ino.bin ./Crown_Display_Thing_v_0_3_0.bin

Project Layout

• 00_Config.ino: constants, pins, defaults, firmware version
• 10_State.ino: runtime state
• 20_MotorLed.ino: motor control and LED rendering
• 22_Scoreboard.ino: scoreboard helpers
• 25_Encoder.ino: rotary encoder behavior
• 30_Sections.ino: section mapping and tuning
• 35_PixelMap.ino: pixel map helpers
• 36_MarqueeExclude.ino: marquee exclusion helpers
• 40_Storage.ino: persistent settings
• 50_Web.ino: web UI, HTTP endpoints, WebSocket
• 60_Network.ino: AP, STA, and mDNS setup
• 90_Main.ino: setup and loop
• Crown_Thing.ino: includes and sketch entry anchor