The quintessential BlueTooth speakers

Prologue

Now it’s very easy to do bluetooth column literally from improvised components. Sold ready bluetooth Audio modules. Here is an example module FSC-DB102 Ver: 1.4

The module is installed on the board FSC-BT1026C V1.2. You can see the chip under the lens QCC3024

Here is his wiring diagram.

block diagram

Since the board must be installed vertically on the stand, I had to measure the dimensions with a caliper

When receiving a printed circuit board (PCB), the first question that an electronic engineer should ask himself is: “where is the ground (GND) on this board?”. It can be called DMM(th)

Similarly nutrition

To turn on the module, just apply power to any USB micro (J1 or J6) and press and hold the Play/Pause (K1) button. The red LED0 will flash. Next, take a smartphone, go to Android ->Settings->Bluetooth. Select Bluetooth on.

Listed AVAILABLE DEVICES appears FSC-BT1026C-LE. The phone will prompt you to pair with FSC-BT1026C. Click PAIR.

After that, the red LED0 on the module has already begun to glow continuously. Now you can open YouTube and listen to the video through the headphones connected to the board FSC-DB102 Ver: 1.4. You can change the sound volume from your phone. You can also stop the video with the PLAY/PAUSE (K1) button on the blue PCB of the module.

Also, when connected via USB via connector J6, COM3. At bit rate 115200 bit/s you can see what the module sends to UART log.

The first thing that comes to mind is what can be done based on this Bluetooth module as a column that will log listened tracks to the SD card. Column with black box.

Communication and interaction with the module is carried out through the AT-Commands protocol over UART. You can use the utility Terminal v1.9b

You can also set up TeraTerm for automatic appending carriage carriage and return to the beginning of the line. Plus, you need to activate the software echo, since the firmware does not send an echo to the UART

Next, you can see that the device is responding to AT commands sent via TeraTerm

Audio transmission over I2S

By itself, the module does not send anything to I2S out of the box, even when the stream is enabled. So I2S needs to be configured somehow. There is an AT command for that. AT-I2SCFG

If you send a command to the UART AT+I2SCFG=65 (65=0x41=0b0100_0001), then the FSC-BT1026C module will become the master on the bus I2S at a sample rate of 48kHz and will send 32-bit PCM samples on the wire PCM-OUT. The bit frequency is 3.012 ….3.086 MHz

At the same time, when sound is transmitted to I2S, sound is not transmitted to the headphones on Audio Jack 3.5mm, which is inconvenient for debugging.

Text transmission over SSP (Serial Port Profile)

The module can transmit not only sound but also text data. In SSP mode, the blue LED1 is lit on the board. You need to install the application on your mobile phone Serial Bluetooth Terminal 1.36

Get Bluetooth chat (ik) at 10 meters.

Project ideas based on the FSC-BT1026 module

1–Device auto-dialer to phone numbers, which will automatically speak some sound and reset or a hardware auto-responder.

2–Bluetooth speaker with content logging function. The title of the YouTube video.

3–Remote control via SSP from phone.

4–Bluetooth SSP chat within 10 meters.

Conclusion

The thing is interesting. May be useful for prototyping.

Dictionary