Small, powered Bluetooth 5.1 stereo transmitter board designed for DIY speaker and headphone projects. Runs from a 5V supply and implements GFSK modulation for reliable wireless audio transmission. Ideal when you need to add Bluetooth TX capability to amplifiers, portable speakers, or custom headphone rigs without redesigning the whole system. Why you need it Turn non‑Bluetooth audio sources into wireless audio transmitters quickly and cleanly. Use in DIY speaker and headphone builds to stream stereo audio to Bluetooth headphones or speakers. Compact boardlevel solution that saves time versus building a wireless link from discrete components. Key benefits Bluetooth 5.1 compatibility: modern protocol support for wide device compatibility and stable connections. GFSK modulation: standard, robust modulation method for Bluetooth Basic Rate audio transmission. 5V power input: easy to integrate with common USB power supplies or existing 5V rails in DIY projects. Stereo audio transmission: preserves left/right channels for full stereo playback. Main features and attributes Functionality: acts as a Bluetooth stereo audio transmitter / wireless transceiver module suitable for integration into speaker or headphone projects. Power: 5V operating supply (boardlevel module). Wireless protocol: Bluetooth 5.1 with GFSK modulation for stereo audio transmission. Intended use: DIY speaker and headphone applications, or any project requiring a compact Bluetooth audio transmitter board. Form factor: compact PCB module (boardlevel component for integration). Designed to be mounted or incorporated into enclosures. Integration: modulelevel solution that pairs with standard Bluetooth sinks (headphones, speakers) compatible with Bluetooth audio. Two practical use cases Add wireless capability to a bookshelf amplifier: Connect the transmitter board to the amplifier's line input and a 5V supply to stream music from phones or tablets to Bluetooth receivers without changing the amplifier electronics. Build a custom Bluetooth headphone system: Integrate the board into a DIY headphone enclosure or portable audio player to send stereo audio wirelessly to Bluetooth headphones or speakers. What to expect in integration Boardlevel module designed for developers and DIYers who are comfortable with basic soldering and wiring. Requires a 5V supply and audio input wiring; mounts and enclosure integration depend on your project layout. Pairs with standard Bluetooth audio sinks that accept Bluetooth 5.1 connections. considerations Intended for hobbyists, makers, audio tinkerers, and smallscale product prototypes. Verify connector and pinout compatibility with your project before installation. This is a transmitter/transceiver board for integration rather than a finished consumer product; some wiring and mounting are required. If you want to add reliable Bluetooth 5.1 stereo transmission to an existing audio design or a DIY speaker/headphone project, this 5V GFSK stereo transmitter board provides a compact, boardlevel solution that minimizes development time while delivering standard Bluetooth audio performance.