Model Number:
bluetooth audio module
M38
MH-M38 is a low-power Bluetooth design that supports the latest Bluetooth 4.2 transmission and two-channel stereo lossless output. Small size, convenient and practical, the module comes with a power amplifier chip, which can be equipped with dual 5W speakers. Support USB sound card for driverless playback. 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.
PCB size: 45*20*3.6mm (length, width and height)
Pin pitch: 2.54mm (positioning hole is 3mm in diameter)
3. Function /Pin definition
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, the maximum working current is 5V2A, it is recommended to use 5V2A regulated power supply, the sound quality is better.
4. After the module is powered on, the mobile phone searches for the Bluetooth name MH-M38, and can play music after connecting to Bluetooth.
5, support USB sound card, free drive (plug and play). Connect the module to the computer with a USB cable, and the computer can play music through the module amplifier output.
6, module blue indicator light:
7. When the Bluetooth is not connected, the indicator light flashes quickly;
8. When the Bluetooth connection is on, the indicator light is always on;
9. When the Bluetooth is playing, the indicator light flashes slowly.
10, audio output: output left and right channel stereo audio signal, can be connected to two 2-8 euro, 3-5W speakers, push 4 Euro 5W speakers.
11, this product has its own dual 5W power amplifier circuit, you must not use another amplifier to use! The outputs of the two amplifiers may not be connected in parallel or the negative poles may be connected together, otherwise the power amplifier chip may be damaged.
4.Atention
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.
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