This M28 device is a Bluetooth low-power solution. It features two-channel stereo playback and Bluetooth 4.2 transmission. For rapid wireless Bluetooth communication, the module can be linked to Bluetooth. The Bluetooth connection may reach 20 meters in an open area. Widely used in a variety of bt audio reception and audio DIY modifications. Bluetooth version V4.2, Bluetooth connection technology, lossless WAV/ WMA/ FLAC/ APE/ MP3 decoding, stereo dual-channel output The mobile phone looks for the Bluetooth name MH-M28 after turning on the module, and after connecting to Bluetooth, it can play music.
Type: Wireless / Bluetooth
Operating temperature: -40 to +85 ° C.
Quantity: 1 piece.
Blue indicator light module:
When no Bluetooth is connected, the indicator light flashes quickly.
When the Bluetooth connection is switched on, the indicator light always lights up.
The indicator light flashes slowly during Bluetooth playback.
1 x Audio Bluetooth Module MH-M28 Wireless Receiver
Pinout of the Module:
|Pin number||Pin header||Description|
|3||VBAT||Lithium battery positive 3.7-4.2V|
|4||L||Left channel output|
|5||R||Right channel output|
1. Power it up:
For direct power supply, you may use the MICRO USB Android cable 5V, or you can connect a 5V power supply or a 3.7V lithium battery (as shown above). The connectors for the 5V and 3.7V power supplies are different. The 3.7V lithium battery is linked to VBAT and GND, while the 5V voltage is connected to 5V and GND.
2. 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).
Warning 1: The charging interface of this product is a current-limiting charging mode without charging management! For the safety of your life and property, please be sure to use a lithium battery with a protective circuit produced by a Known manufacturer. Our company will not bear any responsibility if it is damaged due to improper use!
Warning 2: Pay attention to the following two points when using MH-M28:
Power supply: 5V power supply by default. If you need to use a 3.7V lithium battery for power supply, you need to replace the diode with 0-ohm resistance of 0603 or short the two ends of the pad directly. The shipment defaults to a 5V power supply. If customers need a 3.7V lithium battery power supply, they can be customized in batches. The Bluetooth audio module has very high power requirements, which will affect the audio quality. It is recommended to add an LC filter circuit, especially a switching power supply (such as a mobile phone charger).
MUTE port: When this module is muted, this port outputs a high level of 3.3V and a low level of 0V during playback. If the power amplifier board mute high level is effective, it can be directly connected. If the power amplifier board mute is low-level control, you need to add a reverse circuit.Signal interference: Bluetooth antenna is extremely susceptible to high frequency or strong electromagnetic signal interference. Keep it as far away as possible from sending wireless devices. And the board cannot keep a certain distance next to the metal items.
current sound: from the power amplifier board, the cause is the ground wire interference. It is recommended not to use a plug wire at the output end of the Bluetooth module. It is necessary to weld the wire, especially the ground wire. Thicker. The problem of the audio ground at the ground point of the power amplifier board must be connected to the ground of the audio input end of the power amplifier. This ground point can be tried to weld 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 power amplifier ground.