VHM-314 Bluetooth 5.0 Audio Receiver Board, which is often built around a 24-pin (SOP24)

 

The "BT SOP24" most likely refers to the VHM-314 Bluetooth 5.0 Audio Receiver Board, which is often built around a 24-pin (SOP24) decoder chip. These budget-friendly audio boards—used to make DIY speakers or update car stereos—are often sold in standard and "luxury" versions that include physical audio buttons. [1, 2, 3, 4, 5]

How to Connect Buttons to Your SOP24 Bluetooth Board

If your board has the solder pads for media buttons (typically labeled PREV, NEXT, V+, V-, P/P, VOL+, etc.), they are designed to be wired using tactile momentary push-buttons to the ground:

• V+ (Volume Up): Press once to increase volume.
• V- (Volume Down): Press once to decrease volume.
• PREV (Previous): Press to go to the previous track.
• NEXT (Next): Press to skip to the next track.
• P/P (Play / Pause): Press once to pause/play audio.
• MODE: Some boards have a Mode/EQ button to switch between Bluetooth and AUX/USB mode, or to answer incoming phone calls. [1, 2, 3, 4, 5]

Basic Operation

1. Powering On: Connect the board via the Micro-USB/Type-C port or solder a 3.7V to 5V Lithium-ion battery to the VCC/GND pads.
2. Pairing: The blue indicator light will flash rapidly. Search for a device named "XY_BT" or similar on your phone and connect.
3. Audio Output: Plug your headphones or amplifier into the onboard 3.5mm stereo jack, or use the Left/Right (L-OUT, R-OUT) solder pads. [1, 2, 3, 4, 5]

If you'd like to tailor your setup or troubleshoot further, could you tell me:

1. What specific device or module you are working with?
2. What are the exact labels written next to the button/solder pads on your board?
3. Are you trying to add external buttons via wiring, or are they onboard buttons that aren't working?

To power your SOP24 Bluetooth Audio Board using a TP4056 Lithium Battery Charger, you must wire the components together safely to prevent audio noise and damage.

The TP4056 handles the safe charging and discharging of a 3.7V Lithium-Ion (18650 or Lipoly) battery, which in turn powers the Bluetooth board and your buttons. [1]

Wiring Diagram Guide

You will need to solder four core connections between the TP4056 module, the battery, and the Bluetooth board:

• Battery Connections:
  • Connect the B+ pad of the TP4056 to the Positive (+) terminal of the battery.
  • Connect the B- pad of the TP4056 to the Negative (-) terminal of the battery.
• Power Output to Bluetooth:
  • Connect the OUT+ pad of the TP4056 to the VCC / 5V power pad of the Bluetooth board.
  • Connect the OUT- pad of the TP4056 to the GND power pad of the Bluetooth board.

Note: Use a version of the TP4056 board that features dual protection (it will have 6 solder pads total: IN+, IN-, B+, B-, OUT+, OUT-). Avoid versions with only 4 pads, as they lack over-discharge protection.

Essential Tips for This Setup

• Add a Power Switch: Place a physical toggle switch on the wire between OUT+ on the TP4056 and VCC on the Bluetooth board. Otherwise, the Bluetooth board will stay on constantly and drain your battery.
• Isolate Audio Ground Noise: If you connect this setup to an amplifier that shares the same battery, you will hear loud buzzing/whining noises. You can fix this by using a isolated 5V-to-5V DC converter (like a B0505S) between the TP4056 output and the Bluetooth module.
• Charging: Charge the system safely by plugging a standard USB cable directly into the TP4056 module's input port. Do not power the Bluetooth board directly via its own USB port while the battery is attached.

If you want to make sure your build is seamless, let me know:

• What type of amplifier or speaker are you connecting to the audio output?
• Do you need help adding an LED status indicator to see when the battery is low?