Beatled

Real-time beat-synchronized LED control for live music.

Beatled listens to music through a USB microphone, detects the beat in real time, and synchronizes individually addressable LED strips across multiple wireless devices – all with sub-millisecond precision.

Imagine a party where everyone’s outfit lights up in sync with the music. Sew an LED strip into a jacket, wrap one around a hat, line a stage prop, or embed one in a costume – each one driven by a tiny Pico W microcontroller connected to WiFi. A single Raspberry Pi in the corner picks up the music, finds the beat, and tells every device exactly when to flash. The result: dozens of people pulsing together to the same rhythm, with coordinated color patterns that react to every beat and tempo change.

The LED strips used are WS2812 (also known as NeoPixel) – addressable RGB LEDs where each pixel can be set to any color independently. The firmware ships with 8 built-in patterns (snakes, sparkles, color fades, and more) that are driven by the beat position, and new patterns can be added as simple C functions. The active pattern can be switched live from the web dashboard, and every connected device updates simultaneously.

How It Works

graph LR
    MIC["USB Mic"] --> PI["Raspberry Pi<br/>(Beat Server)"]
    PI -->|UDP| C1["Pico W"] --> LED1["WS2812 LEDs"]
    PI -->|UDP| C2["ESP32"] --> LED2["WS2812 LEDs"]
    PI -->|HTTPS| WEB["React (Web)"]
    PI -->|HTTPS| IOS["iOS"]
    PI -->|HTTPS| MACOS["macOS"]

1. A Raspberry Pi captures audio from a USB microphone and runs real-time beat detection (BTrack algorithm)
2. Beat timing is broadcast over UDP to all LED controllers on the local network
3. Each controller (Pico W, ESP32, or POSIX simulator) uses NTP-style time synchronization to align its clock with the server, then drives a WS2812 LED strip in sync with the beat
4. A web, iOS, or macOS client lets you monitor tempo, switch LED programs, and control services from your phone or computer

Components

Component	Technology	Description
Beat Server	C++ (CMake, ASIO, PortAudio)	Audio capture, beat detection, UDP broadcast, HTTPS API
LED Controller	C (Pico SDK, ESP-IDF, POSIX)	Multi-platform firmware: Pico W, ESP32, macOS/Linux sim
Clients	React / SwiftUI	Web, iOS, and macOS apps for monitoring and LED control
Protocol	Binary UDP	Packed structs for registration, time sync, and beat data

See the Architecture page for detailed diagrams.

Getting Started

Get the server, web client, and Pico simulator running locally in minutes – no hardware required.

Getting Started Guide

Repositories

Repo	Description
beatled	C++ server, React client, Docker build, and documentation
beatled-pico	Pico W firmware (C) with posix test port
beatled-beat-tracker	Fork of BTrack for real-time beat tracking