Product introduction
MH-M28 is a low-power Bluetooth design that supports the latest Bluetooth 4.2 transmission and two-channel stereo lossless playback. Small size, convenient and practical, Bluetooth connection can be quickly realized after the module is connected to Bluetooth, which is very convenient. In an open environment, the Bluetooth connection distance can be up to 20 meters. Can be used for Bluetooth audio reception, various audio DIY modification and so on.
Size
PCB size: 45*20*6.8mm (length, width and height)
Pin pitch: 2.54mm (positioning hole is 3mm in diameter)
1. Bluetooth V4.2 version, support Bluetooth automatic connection technology, support WAV/WMA/FLAC/APE/MP3 lossless decoding, stereo dual channel output.
2, power supply: you can directly use the MICRO USB Android line 5V for direct power supply, you can also connect 5V power supply or 3.7V lithium battery (as shown above). Note that the 5V and 3.7V power supply interfaces are different. 5V is connected to 5V and GND, and the 3.7V lithium battery is connected to VBAT and GND.
3. After the module is powered on, the mobile phone searches for the Bluetooth name MH-M28 and can play music after connecting to Bluetooth.
4, module blue indicator light:
5. When the Bluetooth is not connected, the indicator light flashes quickly;
6. When the Bluetooth is connected, the indicator light is always on;
7. When the Bluetooth is playing, the indicator light flashes slowly.
8. Audio output: The earphone can be directly connected to the 3.5mm audio interface, or it can be wired for the audio input of the power amplifier board (the interface L/R/AGND can  be directly wired as shown).
Application wiring diagram
1. Signal interference: The Bluetooth antenna is extremely susceptible to high frequency or strong electromagnetic signal interference, and it should be placed away from the place where the wireless device is sent. And the board can’t be close to metal objects, keeping a certain distance.
2. If there is current sound in the power amplifier board, the cause is caused by ground
interference. It is recommended that the output of the Bluetooth module should not be plugged in. It is necessary to solder the wire, especially the ground wire, and the wire should not be too long. The shorter the better. , try to be thicker. The problem of audio grounding at the grounding point of the power amplifier board must be connected to the ground of the audio input of the power amplifier. This grounding point can be tried to solder at different positions to achieve the lowest current sound. It is recommended that the Bluetooth and power amplifier boards be powered separately to isolate the Bluetooth ground and the amplifier ground.
3. because this product is bare board design, try not to touch the components on the board by hand, it is easy to cause static electricity to kill the chip and cause burning.
Reviews
There are no reviews yet.