MH-M28 Wireless Bluetooth Audio Receiver Board

MH-M28 Wireless Bluetooth Audio Receiver Board is a compact and efficient module designed to convert any existing audio system into a wireless Bluetooth streaming device. This module utilizes the Bluetooth 4.2 protocol, offering a stable and reliable digital signal transmission over short distances. Consequently, you can easily upgrade old stereo equipment, car audio, or active speakers without complex modifications. The MH-M28 simplifies the process by requiring only a power source (3.7V to 5V) and connections to an amplifier or headphone input. Therefore, makers, hobbyists, and audiophiles frequently choose this board for their DIY audio projects because it provides a cost-effective, high-quality wireless audio solution. Furthermore, its small physical footprint allows for discreet integration into almost any enclosure.

Key Features:

• Bluetooth 4.2 Protocol: Offers stable connectivity, efficient power usage, and compatibility with most modern smartphones and tablets.
• Stereo Output: Provides dedicated Left and Right channel outputs, allowing for true stereo sound reproduction.
• Micro USB Power Input: Easily power the board using a standard 5V Micro USB cable, alternatively a 3.7 V lithium battery connection is available.
• Integrated Status LED: A simple on-board LED indicates the Bluetooth connection status (fast flashing for pairing, slow flashing for connected).
• Compact Design: The extremely small size makes this module ideal for embedding into small enclosures and portable devices.

Technical Specifications:

• Bluetooth Version: Bluetooth V4.2
• Power Supply Voltage: DC 3.7 V − 5 V (Via Micro USB or dedicated pins)
• Signal-to-Noise Ratio (SNR): ≥ 90 dB
• Total Harmonic Distortion (THD+N): ≤ −70 dB
• Crosstalk: ≤ −86 dB
• Supported Profile: A2DP / AVCTP / AVDTP / AVRCP / HFP
• Transmission Distance: ≈ 10 − 15 meters (line of sight)
• Output Impedance: 4 Ω − 8 Ω (If used directly with speakers; typically connected to an amplifier)

Mechanical Specifications:

• Module Material: FR4 PCB
• Pin Pitch: 2.54 mm (Standard header pin spacing)
• Mounting: Solder pads for through-hole male header pins or direct wire soldering.
• Antenna: On-board PCB trace antenna.

Dimensions:

• Length (L): ≈ 25 mm
• Width (W): ≈ 15 mm
• Height (H): ≈ 1.5 mm (PCB thickness, not including header pins)
• Weight: ≈ 1.5 g (Ultra-lightweight)

Pinout and Wiring:

• VCC: Connect this pin to the positive terminal of the 3.7 V (Li-ion battery) or 5 V DC power supply.
• GND: Connect this pin to the common ground of the circuit and power supply.
• L: Connect this pin to the Left audio signal input of an external amplifier.
• R: Connect this pin to the Right audio signal input of an external amplifier.
• M (GND): This pin serves as the common audio ground reference for the L and R output signals.

Datasheet Reference:

• Download MH-M18/M28/M38 Series Audio Module Datasheet

Commonly Used in:

• DIY Portable Speakers: Providing the wireless connectivity core for custom-built speakers.
• Car Audio Upgrades: Adding Bluetooth streaming capability to older car stereo systems.
• Desktop Audio Converters: Converting wired desktop speakers into wireless Bluetooth speakers.

Applications:

• Stereo Retrofitting: Users successfully retrofit vintage audio amplifiers and active speakers with modern wireless capability.
• Headphone Amplifier Projects: Developers integrate the module to create custom wireless headphone amplifiers.
• Wireless Home Audio Zones: You can create multiple, independently controlled wireless audio playback zones across a home.

Equivalent Models:

• MH-M18 / MH-M38: Functionally similar modules in the same series, however, the M38 often includes an on-board amplifier.
• VHM-314: A comparable low-cost Bluetooth audio receiver module, sometimes featuring Bluetooth 5.0.
• XY-BT-Mini: Another widely used, compact Bluetooth receiver board that offers similar basic audio receiving functionality.

Package Includes:

• 1 x MH-M28 Wireless Bluetooth Audio Receiver Board