Technical Architecture

Window Wordsmith relies on a modern, decoupled architecture connecting a cross-platform mobile application with a powerful, dual-core embedded driver over a custom binary Bluetooth protocol.

The Mobile Client

The user-facing client is a native mobile application designed for speed and reliability in the car.

• Framework: Built as a Bare React Native application (TypeScript).
• Storage: Fully local database implementation (NoSQL/SQLite) ensuring user presets, connection details, and app configuration persist across sessions without relying on a remote API.
• Connectivity: Leverages native OS Bluetooth APIs to scan, pair, and maintain connections with the hardware display.

The LED Matrix Driver

The hardware component sits in the rear windshield, translating Bluetooth commands into visual displays.

• Core 0 (Networking): Dedicated exclusively to managing the Bluetooth Classic connection and processing incoming packet events.
• Core 1 (Rendering): Dedicated to pulling messages from the thread-safe queue and rendering the visual data to the LED matrix screen.

Communication Protocol

To ensure maximum reliability and prevent rendering stuttering, Window Wordsmith avoids heavy JSON processing in favor of a lightweight, custom binary frame structure over a Bluetooth SPP (Serial Port Profile) stream.

The binary packet includes:

• 0xAA 0x55 - Sync Headers
• Protocol Version
• Foreground & Background RGB Color data
• Animation Transition ID
• Data Length & UTF-8 Text Payload
• CRC-8 Checksum for data integrity