Product Description
This product MH-M18 is a low-power Bluetooth design solution, supporting the latest Bluetooth 4.2 transmission, Bluetooth automatic reconnection technology, WAV/WMA/FLAC/
APE/MP3 lossless decoding, and dual-channel stereo lossless playback. After the module is connected to Bluetooth, Bluetooth wireless transmission can be quickly realized, which is very convenient. In an open environment, the Bluetooth connection distance can reach 20 meters. It is widely used in various Bluetooth audio reception, various audio DIY modifications, etc.
Instructions for use:
After the module is powered on, search the Bluetooth name MHM18 on the phone and connect to Bluetooth
You can play music after that. The functions of the blue indicator light on the module are as follows:
1. When Bluetooth is not connected, the indicator light flashes quickly
2. When Bluetooth is connected, the indicator light is always on
3. When Bluetooth is playing, the indicator light flashes slowly.
| Number | Pin | Description |
| 1 | KEY | Key control terminal (4 key functions, additional resistors are required |
| 2 | MUTE | Mute control terminal (output high level 3.3V when muted, output low level when playing) |
| 3 | VCC | Power supply positive pole 5V (3.7V lithium battery power supply requires short-circuit diode) |
| 4 | GND | Power supply negative pole |
| 5 | L | Left channel output |
| 6 | R | Right channel output |
The module interface adopts a half-hole process, and customers can directly mount or weld it on the board.
Precautions
Signal interference: Bluetooth antennas are extremely susceptible to high-frequency or strong electromagnetic signal interference. Try to place them away from wireless devices. And the board should not be close to metal objects. Keep a certain distance.
If there is a current sound when connecting to the power amplifier board, the cause is ground interference. It is recommended not to use a plug-in cable at the output end of the Bluetooth module. The wire must be welded, especially the ground wire. The wire cannot be too long. The shorter the better, and it should be as thick as possible. The problem of the audio ground at the grounding point of the power amplifier board must be connected to the ground of the audio input end of the power amplifier. This grounding point can be tried to be welded at different positions to achieve the lowest current sound. It is recommended to power the Bluetooth and power amplifier board separately to isolate the Bluetooth ground and the 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 can easily cause static electricity to kill the chip and cause it to burn.
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