SPECIFICATIONS

Brand Name: NONE

Condition: New

High-concerned chemical: none

Origin: Mainland China

Package: SMD

Type: Module

This product MH-M18/M28/M38 is a low-power Bluetooth design solution, support the new Bluetooth 4.2 transmission, dual-channel stereo lossless playback, the module is connected to the Bluetooth, you can quickly realize the Bluetooth wireless transmission, very convenient. Under the open environment, the Bluetooth connection distance can reach 20 meters.

Widely used in a variety of Bluetooth audio reception, all kinds of audio DIY modification, etc..

For the different needs of customers, we provide 3 versions for you to choose:

Function Description:

Bluetooth V4.2 version, support bluetooth automatic back-connection technology, support WAV/WMA/FLAC/APE/MP3 lossless decoding, stereo dual-channel output.

After the module is powered on, the cell phone searches for the Bluetooth name MH-M18/MH-M28/MH-M38, and you can play music after connecting to Bluetooth;

Module blue indicator light:

When Bluetooth is not connected, the indicator light flashes fast;

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

When Bluetooth is playing, the indicator light flashes slowly.

The following is a description of each version:

MH-M18:

The module interface adopts half-hole process, customers can directly patch or solder on the board.

1 KEY key control terminal (4 keys function, need to add another resistor)

2 MUTE mute control terminal (mute output high level 3.3V, playback output low level)

3 VCC power supply positive 5V (lithium battery 3.7V power supply requires a short-circuit diode)

4 GND power negative

5 L Left channel output

6 R Right channel output

MUTE mute control terminal: used to control the amplifier board, MUTE output high level 3.3V when mute, output low level when play.

KEY button control: This function needs to connect resistor and button separately to realize.

Volume Hold Function: Default output volume. Control the volume increase and decrease by key, if the control volume is less than 15%, the volume output will be 15% after re-power on; if the control volume is more than 15%, the original volume will be kept unchanged after re-power on.

MH-M28: 1. Power supply: you can directly use the MICRO USB Android cable 5V direct power supply, you can also access another 5V power supply or 3.7V lithium battery. Note that 5V and 3.7V power supply interface is not the same, 5V voltage connected to the 5V and GND, 3.7V lithium battery connected to the VBAT and GND.

2. Audio output: headphones can be directly connected to the 3.5mm audio interface, can also be wired for the audio input of the amplifier board (interface L/R/AGND can be wired directly).

MH-M38: 1. Power supply: you can directly use the MICRO USB Android cable 5V direct power supply to use, you can also additionally access the 5V power supply or 3.7V lithium battery. Note that 5V and 3.7V power supply interface is not the same, 5V connected to 5V and GND, 3.7V lithium battery connected to VBAT and GND.

Operating current 5V2A, it is recommended to use 5V2A regulated power supply power supply, better sound quality.

2. Support USB sound card, driver-free (plug and play). USB cable will be connected to the module and the computer, the computer can play music through the module amplifier output

3. Audio output: output left and right channel stereo audio signals, can be connected to two 2-8 ohm, 3-5W speakers, 4 ohm 5W speakers for push memory.

4. This product has its own dual 5W amplifier circuit, do not connect another amplifier to use! The output of the two amplifiers can not be connected in parallel or the negative pole connected together, or damage to the amplifier chip.

Attention

Signal interference: Bluetooth antenna is extremely susceptible to high-frequency or strong electromagnetic signal interference, try to be placed away from the sending wireless and other equipment. And the board can not be close to metal objects, keep a certain distance.

If you connect the amplifier board current sound, caused by ground interference caused by the cause, it is recommended that the output of the Bluetooth module do not use the plug line, the need to weld the line, especially the ground line to be welded, and the line can not be too long, the shorter the better, try to be thicker. Audio ground in the amplifier board grounding issues, must be connected to the ground in the audio input of the amplifier, the ground can try to weld in different locations to achieve the current sound. It is recommended that the Bluetooth and amplifier board separate power supply, isolate the Bluetooth ground and amplifier ground.

As this product is a bare board design, try not to touch the components on the board with your hands, it is easy to lead to static electricity killed the chip resulting in burned.

Warning: The charging interface of this product is current-limited charging mode, without charge management! For the safety of your life and property, please be sure to use the regular manufacturers of lithium batteries with protection plate, if the loss caused by improper use, the company does not assume any responsibility!

Another: for MH-M18 use need to pay attention to the following two points:

Power supply: 5V power supply by default. If you need to use 3.7V lithium battery power supply, you need to replace the diode 0603 0 ohm resistor, or directly short circuit the pads on both sides.

Bluetooth audio module on the power supply requirements are very high will affect the quality of the audio, it is recommended to join the LC filter circuit, especially switching power supply power supply (such as cell phone chargers, etc.).

MUTE mute port: this module is muted when the port output high level 3.3V, playback output low level 0V. amplifier board mute high level is valid if you can directly access. If the mute level of the amplifier board is low level control, you need to add the reverse circuit.