This Bluetooth audio module is a compact and versatile solution for wireless audio applications. With a built-in Bluetooth antenna and mono and stereo output support, this module is perfect for adding Bluetooth functionality to common power amplifiers and active speakers. Operating at a 5V power supply, it features a 7-pin output interface, including power, ground, left and right channels, mute, LED status indication, and a reserved port. The LED status port helps monitor Bluetooth connection states, flashing rapidly when not connected and slowly when successfully paired. Compact and easy to integrate, this module is ideal for DIY audio projects and custom speaker builds.

Features

• Mono and Stereo Output: Flexible audio output options for different audio needs.
• Built-in Bluetooth Antenna: Ensures stable and reliable Bluetooth connectivity.
• Compact Design: Dimensions of 30mm x 20mm x 3mm make it easy to fit in small enclosures.
• 7-Pin Output Interface: Simplifies connections with clearly designated pins.
• LED Status Indicator: Quickly shows Bluetooth connection status with fast or slow flashes.
• Wide Operating Voltage Range: Works within 4.1V to 5V, protecting against high voltage damage.

Specifications

• Power Supply Voltage: 4.1V - 5V (Do not exceed 5.1V)
• Dimensions: 30mm x 20mm x 3mm
• Output Interface: 7-pin 2.54mm through-hole
• Bluetooth Status LED: Rapid flash for no connection, slow flash for successful connection

Pinout and Wiring

1. +5V Power Supply: Connects to the positive terminal of a 4.1V–5V power source.
2. Ground (GND): Negative terminal of the power supply and audio ground.
3. Left Channel: Connects to the left channel input of an amplifier or headphones.
4. Right Channel: Connects to the right channel input of an amplifier or headphones.
5. Mute Output Port: Outputs high level by default, low level when muted.
6. Status Indicator: LED flashes rapidly when Bluetooth is not connected and slowly when paired.
7. Reserved Port: Pulled up to 5V; triggers shutdown when set to low level

Note: Use soldering for connections to avoid noise introduced by contact resistance. Ensure power supply voltage stays within the specified range to prevent damage.

Precautions

1. Power Supply: This Bluetooth audio module is sensitive to high-frequency interference. For best performance, use a linear regulated power supply. If using a DC-DC power supply, add an LC filter to minimize harmonic interference. Avoid using switch-mode power supplies like mobile phone chargers, as their voltage output often exceeds the safe range (5.1V to 5.4V), which can damage the module.
2. Grounding: Proper grounding is essential to avoid audio interference. Solder two separate ground connections: one to the power supply’s negative terminal (GND) and another to the audio input ground of the amplifier board. Avoid using lead wires, as they are prone to interference.
3. Antenna Interference: Keep the Bluetooth antenna away from high-frequency or strong electromagnetic signals, like those from amplifier boards. Avoid placing the antenna near metal objects, which can weaken the signal.
4. Enclosure Considerations: If using a metal enclosure for your project, note that it can shield and weaken the Bluetooth signal. Ensure proper openings or expose the antenna for better reception.

Power Supply Separation: If interference persists, consider using separate power supplies for the amplifier board and the Bluetooth module.

Common Issues and Solutions

1. Current Noise: Ground interference often causes unwanted noise. Ensure output terminals of the Bluetooth module are properly soldered — especially the ground wire — keeping the connections short and thick. Separate the power ground and audio ground wires. For the amplifier board, try different grounding points to minimize noise.
2. Weak Bluetooth Signal: If Bluetooth range is limited to less than 5 meters, the power supply likely introduces interference. Ensure a stable voltage and add a diode and capacitor to filter the power supply noise.
3. Bluetooth Not Detected: High power supply ripple or voltage fluctuations can disrupt the Bluetooth signal. Ensure a clean power source and proper voltage regulation. If a phone has been connected to multiple modules with the same Bluetooth name, delete the old connection and search again.
4. Noise Issues: There are two types of noise:
   • Bluetooth Standby Noise: A low-level noise during Bluetooth standby can be minimized using the mute (MUTE) function.
   • Interference Noise: Caused by improper wiring or grounding. Ensure the shortest and most direct ground connections to reduce noise.

Package Includes

• 1 x Bluetooth Audio Module