Port Description:
1. +5V power supply: connect the positive pole of the power supply, the voltage range is 4.1V~5V, please ensure that the power supply is within this range. Exceeding this range may damage the module or cause the work to be abnormal;
2, ground: GDN is connected to the negative pole of the power supply, which is also the ground of audio. This place must be separated from the ground and the audio ground separately.
3. Left channel: Connect the left channel input of the power amplifier board or the left channel of the earphone. It is recommended to connect a capacitor to the output port (depending on the input matched by the power amplifier);
4. Right channel: Connect the right channel input of the power amplifier board or the right channel of the earphone. It is recommended to connect a capacitor to the output port (depending on the matching input of the power amplifier);
5, mute output port: the port is preset to a high level, when the mute, the port outputs a low level;
6. Status indicator: When the Bluetooth is not connected, the light flashes quickly, and once the Bluetooth connection is successful, it will flash slowly;
7. Reserved port: The port has been pulled up to 5V. When the port is triggered by a low level, it will be turned off. When the port is turned back to the low level again.
Please Note: From the Bluetooth audio module to the power supply or to the audio interface, please use the soldering method, do not use the way of plugging, the contact resistance will introduce noise.
Precautions:
1. Power supply: The Bluetooth audio module is a circuit sensitive to high-frequency interference. It is recommended to use a linear regulated power supply. If DC-DC power supply is used, please add LC filter to reduce the harmonic interference of the power supply, especially the switch such as mobile phone charger. Power supply, power supply ripple may cause Bluetooth to not connect properly, and this type of 5V output is often between 5.1V and 5.4V, exceeding the working voltage of the Bluetooth audio module;
When using a switching power supply such as a mobile phone adapter, please add this power supply circuit, the inductance can not be added.
2. Grounding: Since the audio signal is sensitive to the interference caused by the grounding point, two grounding knots can be soldered on the output pin of the Bluetooth module, one is connected to the negative pole (GND) of the power supply, and the other is connected to the power amplifier board. Audio input ground, try to solder on the circuit board, do not use lead wire connection (susceptible to interference), and it is recommended to try the grounding point to minimize interference;
3. Antenna interference: Bluetooth antenna is extremely vulnerable to high frequency, or strong electromagnetic sig nal interference, relatively far away from the strong signal of the power amplifier board, and the antenna can not be close to metal objects, to maintain a certain distance;
4. The outer casing shielding: because the metal casing of the casing has a shielding effect on the Bluetooth signal, it may attenuate the Bluetooth signal to cause poor reception, please keep the corresponding opening, or exposed.
Note: For some power amplifier boards that are susceptible to interference and interference is not easy to handle, please separate the power supply, that is, the power amplifier board is powered by one power supply, and the Bluetooth module supplies power all the way.
Common problem handling:
1. Current sound:
The cause is caused by ground interference. It is recommended that the output terminals of the Bluetooth module do not need to be soldered with the output terminals of the plug-in. In particular, the ground wire should be soldered, and the line should not be too long. The shorter the better, the thicker. In the ground wire drawn from the Bluetooth module, the power ground and the audio ground must also be separated, and it is not possible to connect only one ground wire. 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. Separate power supply is a better way to solve this current sound.
2. The Bluetooth signal is weak:
When the module can work normally, the Bluetooth indicator light flashes normally. The receiving distance of Bluetooth is very close, it can't exceed 5 meters. Generally, there is interference in the power supply (switching power supply interference), or the power supply voltage is abnormal. Please refer to the processing switch of the document. Add that diode and capacitor when the power supply interferes.
3. Bluetooth can not find the signal:
An important reason for not finding the Bluetooth signal is that the power supply is caused. Except that the power supply voltage is abnormal, the ripple of the power supply is generally too high, causing great interference to the high-frequency signal of the Bluetooth module. The method can be handled. In another case, the same mobile phone is connected to multiple modules. Although the Bluetooth numbers are the same, but the internal addresses are different, you can delete the original Bluetooth number and then search for the connection.
4. Noise processing:
There are two kinds of noise reduction, one is the inherent noise of the Bluetooth processing standby search signal, but the sound is not very large, only a little bit, it may be processed by muting (MUTE). Another type of noise floor is caused by interference or wiring, and the modified line can be solved by improving the grounding point. It can be handled in accordance with the method described above.
Package Included:
1 x 5V Mono Stereo Bluetooth Receiver Audio Module
