Product Introduction:
MH-M18 / M28 / M38 is a low-power Bluetooth-compatible design solution that supports the latest Bluetooth-compatible 4.2 transmission, two-channel stereo lossless playback, and Bluetooth-compatible wireless transmission when the module is connected to Bluetooth-compatible, which is very convenient , In an open environment, the Bluetooth-compatible connection distance can be up to 20 meters.
Widely used in a variety of Bluetooth-compatible audio reception, a variety of audio DIY change.
Function:
1. Bluetooth-compatible V4.2 version, support Bluetooth-compatible automatic connection technology, support WAV / WMA / FLAC / APE / MP3 lossless decoding, stereo dual channel output.
2. After the module is powered on, the cell phone searches for the Bluetooth-compatible name MH-M18 / MH-M28 / MH-M38, and can play music after connecting Bluetooth-compatible.
3. Module blue indicator:
When Bluetooth-compatible is not connected, the indicator flashes quickly; when Bluetooth-compatible is connected, the indicator is always on; when Bluetooth-compatible is playing, the indicator blinks slowly
MH-M18
Pin definition:
KEY : Button control terminal (4 button functions, additional resistance required)
MUTE: Mute control terminal (output high level 3.3V when muting, output low level during playback)
VCC: Positive 5V power supply (Lithium battery 3.7V power supply requires short circuit diode)
GND: negative power supply
L: Left channel output
R: Right channel output
Feature:
Control terminal: used to control the power amplifier board. When muting, MUTE outputs a high level of 3.3V, and outputs a low level during playback.
KEY button control: This function requires additional connection of resistors and buttons.
Volume power off function: The default output is 100% volume. Press the button to control the volume increase and decrease. If the control volume is less than 15%, the volume output will be 15% after re-powering; if the control volume is greater than 15%, the original volume will remain unchanged after power-on.
MH-M28
Pin definition:
5V: Power positive 5V
GND: Negative power supply
VBAT: Lithium battery positive 3.7-4.2V
L: Left channel output
R: Right channel output
AGND: audio ground
Feature:
Power supply: It can be directly powered by the MICRO USB Android cable 5V, or it can be connected to a 5V power supply or a 3.7V lithium battery. Note that the 5V and 3.7V power supply interfaces are different. The 5V voltage is connected to 5V and GND, and the 3.7V lithium battery is connected to VBAT and GND.
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 (interface L/R/AGND can be directly wired).
MH-M38
Pin definition:
5V: Power positive 5V
GND: negative power supply
VBAT: Lithium battery positive 3.7-4.2V
L+/L-: Left channel output (direct speaker)
R+/R-: Right channel output (direct speaker)
Feature:
Power supply: It can be directly powered by the MICRO USB Android cable 5V, or it can be connected to a 5V power supply or a 3.7V lithium battery. 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.
The maximum operating current is 5V2A. It is recommended to use a regulated power supply of 5V2A for better sound quality.
Support USB sound card, free drive (plug and play). Connect the module to the computer with the USB cable, and the computer can play music through the module amplifier output.
Audio output: output left and right stereo audio signals, which can be connected to two 2-8 ohm, 3-5W speakers, and 4 Euro 5W speakers.
This product has its own dual 5W power amplifier circuit, and must not be connected to another amplifier! The outputs of the two amplifiers cannot be connected in parallel or the negative poles are connected together, otherwise the power amplifier chip is damage
