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Description:
This product
mh-m18 /M28/M38 is a low power bluetooth design scheme, support the
latest bluetooth 4.2 transmission, dual sound channel stereo lossless
playback, module connected to bluetooth, you can quickly achieve
bluetooth wireless transmission, very convenient.
Open environment, bluetooth connection distance up to 20 meters.
Widely used in all kinds of bluetooth audio reception, all kinds of audio DIY modification.
Function declaration:
1. Bluetooth V4.2 version, support bluetooth automatic connect
technology, support WAV/WMA/FLAC/APE/MP3 lossless decoding, stereo dual channel output.
2. After the module is powered on, the phone searches for the bluetooth
name mh-m18 / mh-m28 / mh-m38. After connecting the bluetooth, music can be played.
Module blue indicator light:
3. Module blue indicator light:
The indicator flashes when the bluetooth is not connected
The indicator light is always on when the bluetooth is connected；
The indicator light flashes slowly while the bluetooth is playing.
SIZE:M18:22.8mm*16mm M28:45.2mm*20.2mm M38:45mm*20.3mm
Note:
1. Signal
interference: bluetooth antenna is very vulnerable to high frequency or
strong electromagnetic signal interference, as far
as possible away
from the sending wireless devices and other places. And the board should
not be close to the metal objects, keep a certain distance.
2. If there is
current sound on the receiving power amplifier board, which is caused by
ground wire interference, it is suggested that the output end of
Bluetooth module
should not use plug wire, welding wire is necessary, especially the
ground wire to be welded, and the wire should not be
too long, the
shorter the better, as thick as possible. The problem of audio ground at
the receiving point of the power amplifier board must be at
the receiving
point of the audio input of the power amplifier. It is recommended that
the bluetooth and power amplifier board be separately powered, isolating
the bluetooth
ground and power amplifier ground.
3. As this product
is designed for bare board, try not to touch the components on the
board with your hands, which may easily lead to electrostatic killing
and chip burning.
Warning: the
charging interface of this product is current limited charging mode,
without charging management! For the safety of your life and property,
please be sure to use the lithium battery with protection plate produced
by the regular manufacturer.
In addition, the following two points should be paid attention to when using mh-m18:
Power supply: 5V
power supply by default. If the 3.7v lithium battery is needed for power
supply, it is necessary to replace the diode with 0603 ohm resistor, or
simply short out the ends of the solder pad.
Bluetooth audio
module has very high requirements on power supply, which will affect the
audio quality. It is recommended to add LC filter circuit, especially
the power supply of switching power supply (such as mobile phone
charger).
MUTE port: this
module outputs a high 3.3v when MUTE, and a low 0V when playback. Power
amplifier board mute high level is valid if you can directly access. If
the amplifier board mute is low level control, need to add the reverse
circuit.
Preview:
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