MH-MX8 Bluetooth Audio Module

Product Description:

This product MH-M18 / M28 / M38 is a low-power Bluetooth design scheme. It supports the latest Bluetooth 4.2 transmission and dual channel stereo lossless playback. After the module is connected to Bluetooth, it can quickly realize Bluetooth wireless transmission, which is very convenient. In an open environment, the Bluetooth connection distance can reach 20m. It is widely used in various Bluetooth audio reception, various audio DIY modification, etc. According to the different needs of customers, we provide 3 versions for you to choose from:

Function Description:

Bluetooth V4 2. Support Bluetooth automatic connection technology, WAV / WMA / FLAC / APE / MP3 lossless decoding and stereo dual channel output. After the module is powered on, the mobile phone searches for the Bluetooth name MH-M18 / MH-M28 / MH-M38, and music can be played after connecting to Bluetooth;

Module Blue Indicator:

When Bluetooth is not connected, the indicator flashes;

When Bluetooth is connected, the indicator light is always on;

When Bluetooth is playing, the indicator flashes slowly.

The Following Is An Introduction To Each Version:

MH-M18：

The module interface adopts half hole process, and customers can directly patch or weld it on the board.

MUTE mute control terminal: used to control the power amplifier board. MUTE outputs a high level of 3.3V during mute and a low level during playback.

KEY key control: this function can be realized only by connecting resistance and key. (the corresponding resistance is shown in the wiring diagram)

Volume power off hold function: output 100% volume by default. Press the key to control the volume increase and decrease. If the control volume is less than 15%, the volume output will be 15% after power on again; If the control volume is greater than 15%, keep the original volume unchanged after power on again.

1. Power supply: you can directly use the 5V MICRO USB Android cable for power supply, or connect another 5V power supply or 3.7V lithium battery (as shown in the figure below). 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. The maximum working current is 5V2A. It is recommended to use 5V2A regulated power supply for better sound quality.

2. Support USB sound card and drive free (plug and play). Connect the module with the computer with USB data cable, and the computer can play music through the power amplifier output of the module

3. Audio output: output stereo audio signals of left and right channels, which can be connected to two 2-8 euro and 3-5w speakers respectively, and 4 Euro 5W speakers for push storage.

4. This product has its own dual 5W power amplifier circuit, so it must not be connected to another power amplifier! The outputs of the two power amplifiers cannot be connected in parallel or the negative electrodes can be connected together, otherwise the power amplifier chip will be damaged.

Matters Needing Attention:

Signal interference: the Bluetooth antenna is extremely vulnerable to high-frequency or strong electromagnetic signal interference. Try to place it away from the place where wireless and other devices are transmitted. And the board can't be close to the metal objects and keep a certain distance. If there is current sound on the power amplifier board, the cause is the interference of the ground wire. It is recommended that the output end of the Bluetooth module should not use plug-in wire and welding wire. The ground wire should be welded, and the wire should not be too long. The shorter the better, and thicker as possible. The problem of audio grounding in the grounding point of the power amplifier board is connected to the grounding of the audio input end of the power amplifier. This grounding point can be welded at different positions to reduce the current and sound. It is recommended that Bluetooth and power amplifier board be powered separately to isolate Bluetooth ground and power amplifier ground. Since this product is designed as a bare board, try not to touch the components on the board with your hands, which is easy to cause static electricity and burn the chip.

Warning:

The charging interface of this product is current limited charging mode, without charging management! For the safety of your life and property, use the lithium battery with protective plate produced by the regular manufacturer. If the loss is caused by improper use, the company will not bear any responsibility!

In Addition:

For MH-M18, the following 2 points should be paid attention to:

The power requirements of Bluetooth audio module will affect the quality of audio. It is recommended to add LC filter circuit, especially switching power supply (such as mobile phone charger).

MUTE Port:This module outputs high level 3.3V when mute and low level 0V when playing. If the mute high level of the power amplifier board is effective, it can be connected directly. If the mute of the power amplifier board is controlled by low level, the reverse circuit needs to be added, as shown in the following figure: