Wireless Bluetooth Audio Module 4.2 Stereo HiFi DIY Modification

 

 

 

 

Product Introduction:

This ProductMH-M18/M28/M38Designed for Bluetooth LE and Supports New Bluetooth4.2Transmission, Two-Channel Stereo Lossless Playback, after the Module Is Connected to Bluetooth, Bluetooth Wireless Transmission Can Be Quickly Realized. In an Open Environment, the Bluetooth Connection Distance Can Reach20Rice.

Widely Used in All Kinds of Bluetooth Audio Reception, All Kinds of AudioDIY Modification, Etc.

 

According to Different Needs of Customers, We Provide3Version One for You to Choose from:

Function Description:

1. Bluetooth V4.2 Supports Bluetooth Automatic Back-to-Back Technology, WAV/WMA/Flac/Ape/MP3 Lossless Decoding, and Stereo Dual Channel Output.
2. After the Module Is Powered on, the Mobile Phone Searches for the Bluetooth Name MH-M18/MH-M28/MH-M38, and Can Play Music after Connecting to Bluetooth;
3. Module Blue Indicator:

When Bluetooth Is Not Connected, the Indicator Light Flashes Quickly;

When Bluetooth Is Connected, the Indicator Light Is Always on;

When Bluetooth Is Playing, the Indicator Light Flashes Slowly.

 

The following Is an Introduction to Each Version:

MH-M18：

The Module Interface Adopts Half-Hole Technology, and Customers Can Directly Patch Or Weld It on the Board.

 

 

No.PinDescription1KEYKey-Press Terminal (4 One Button Function, Additional Resistance Is Required2MUTEMute Control Terminal (Output High Level 3.3V When Mute, Output Low Level When Playing)3VCC5V Positive Electrode of Power Supply (Short Circuit Diode Is Required for 3.7V Power Supply of Lithium Battery)4GNDPower Negative Pole5LLeft Channel Output6RRight Channel Output

 

 

 

 

Mute Mute Control Terminal: Used to Control Amplifier Board. When Mute, Mute Outputs a High Level of 3.3V and a Low Level during Playback.

Key Key-Press: This Function Can Only Be Realized by Connecting Resistor and Button. (The Corresponding Resistance Is Shown in the Wiring Diagram)

Volume Power-off Maintenance Function: the Default Output Volume. The Volume Is Increased and Decreased by Key-Press. If the Control Volume Is Less than 15%, the Volume Output Will Be 15% after Power-on. If the Control Volume Is Greater than 15%, the Original Volume Will Remain Unchanged after Power-on.

MH-M28：

 

No.PinDescription15V5V Positive Electrode of Power Supply2GNDPower Negative Pole3VBATLithium Battery Cathode 3.7-4.2V4LLeft Channel Output5RRight Channel Output6AGNDAudio Ground

1. Power Supply: You Can Directly Use Micro USB Android Line 5V for Power Supply, Or Connect to 5V Power Supply Or 3.7V Lithium Battery (as Shown in the following Figure). Note That the Power Supply Interfaces of 5V and 3.7V Are Different. 5V Voltage Is Connected to 5V and GND, and 3.7V Lithium Battery Is Connected to VBat and GND.

2. Audio Output: the Headset Can Be Directly Connected to the 3.5mm Audio Interface Or Wired for Amplifier Board Audio Input (the Interface L/R/AGND Shown in the Figure Can Be Directly Wired).

 

 

MH-M38：

 

 

No.PinDescription15V5V Positive Electrode of Power Supply2GNDPower Negative Pole3VBATLithium Battery Cathode 3.7-4.2V4L /L-Left Channel Output (Directly Connected to Speaker)5R /R-Right Channel Output (Directly Connected to Speaker)

1. Power Supply: You Can Directly Use Micro USB Android Line 5V for Power Supply, Or You Can Also Connect 5V Power Supply Or 3.7V Lithium Battery (as Shown in the following Figure). Note That the Power Supply Interfaces of 5V and 3.7V Are Different. 5V Is Connected to 5V and GND, and 3.7V Lithium Battery Is Connected to VBat and GND.

Large Work Current 5v2a, It Is Recommended to Use 5v2a Stabilized Power Supply for Power Supply.

2. Support USB Sound Card, Driver-Free (Plug and Play). Connect the Module to the Computer with USB Data Cable, and the Computer Can Play Music through the Module Amplifier Output

3. Audio Output: Output the Stereo Audio Signal of the Left and Right Channels. Two Speakers of 2-8 Euros and 3-5W Can Be Connected Respectively, and 4 Euros and 5W Speakers Can Be Used for Pushing and Storing.

 

4. This Product Has Its Own Dual 5W Power Amplifier Circuit, and Cannot Be Used by Another Power Amplifier! the Outputs of the Two Power Amplifiers Cannot Be Connected in Parallel Or the Negative Poles Are Connected Together, Which Will Damage the Power Amplifier Chip.

 

 

• Precautions

1. Signal Interference: Bluetooth Antenna Is Vulnerable to High Frequency Or Strong Electromagnetic Signal Interference, and Should Be Placed Far Away from Sending Wireless Devices. And the Board Cannot Be next to Metal Objects, Keeping a Certain Distance.

 

1. If There Is Electric Current Sound Connected to Amplifier Board, the Cause Is Caused by Ground Wire Interference. We Recommend That You Do Not Use Incense Inserted at the Output of the Bluetooth Module, but Bonding Wire, Especially If the Ground Wire Needs to Be Welded, and the Wire Cannot Be Too Long, the Shorter the Better, try to Be Thicker. The Problem That the Audio Field Is Amplifier Board Touchdown Should Be Connected to the Audio Input Terminal of the Power Amplifier. This Touchdown Can Be Welded at Different Positions to Achieve Low Current Sound. We Recommend That Bluetooth and Amplifier Board Be Powered Separately to Isolate the Bluetooth Ground and the Power Amplifier Ground.

 

1. Because This Product Is Designed for Bare Board, Try Not to Touch the Components on the Board with Your Hands, Which Will Easily Lead to Static Electricity Killing the Chip and Burning.

 

Warning: Charging Interface of This Product Is the Current Limiting Charging Mode without Charging Management! For the Safety of Your Life and Property, Please Be Sure to Use Lithium Batteries with Protective Plates Produced by Regular Manufacturers. If Losses Are Caused by Improper Use, Our Company Will Not Bear Any Responsibility!

in Addition, Pay Attention to the following Two Points When Using MH-M18:

Power Supply: 5V Power Supply Is Used by Default. If You Need to Use 3.7V Lithium Battery for Power Supply, You Need to Replace the Diode (as Shown in the Figure) with a 0603-Ohm Resistor, Or Directly Short-Circuit Both Ends of the Pad.

Bluetooth Audio Module Has Very High Requirements on Power Supply, Which Will Affect the Quality of Audio. It Is Recommended to Add Lc Filter Circuit, Especially Switching Power Supply (Such as Mobile Phone Charger, Etc.).

 

Mute Port: This Module Outputs a High Level of 3.3V When Mute, and a Low Level of 0V When Playing. If the Amplifier Board Mute High Level Is Valid, You Can Directly Access It. IF Amplifier Board Mute Is Levcon Level Control Lower, You Need to Add a Reverse Circuit, as Shown in the following Figure: