MP3 amplifier module

The 2W MP3 module with integrated amplifier is a compact, self-contained solution for playing audio files directly from a MicroSD card or USB flash drive, without requiring a microcontroller to operate. The board integrates the MP3 decoder, audio amplifier, and power stage on a single 45 x 36 mm PCB, making it suitable for DIY projects such as music boxes, custom doorbells, sound alerts, audio guides, interactive toys, or small announcement systems. Playback is controlled by the four tactile buttons on the board, which allow you to go to the previous or next track, adjust volume by long press, start and stop playback, switch between TF card mode and USB stick mode, and select single-track repeat or repeat-all mode.

Power can be supplied at 5VDC via the MicroUSB port or directly from a 3.7VDC Li-Ion battery connected to the dedicated BAT+ and BAT- pins; the MicroUSB port also serves to charge the battery. Audio output is available either through the gold-plated 3.5 mm jack, for connecting headphones or an external amplifier, or through the two-position screw terminal, to which a passive speaker can be connected directly. The amplifier is mono, with a single channel, and the recommended speaker is 3W and 4 Ohms for balanced sound and no distortion at high volume.

Although the module operates completely independently, it can be easily integrated into projects based on Arduino UNO, Nano, Mega, ESP32, ESP8266, STM32, or other compatible platforms by controlling the board buttons using the microcontroller's digital pins, transistors, or optocouplers. This approach allows automatic playback triggering based on a sensor, an external button, or a command received over the network, while preserving the simplicity and reliability of a dedicated audio player.

Specifications:

Type: MP3 decoder module with integrated audio amplifier

Supply voltage: 5VDC or 3.7VDC battery

Amplifier power: 2W

Channels: 1, mono

Recommended speakers: 3W, 4 Ohms

Supported media: MicroSD (TF) card and USB flash drive

Supported audio format: MP3

Audio output: gold-plated 3.5 mm jack and 2-position screw terminal

MicroUSB port: battery charging and power supply

Battery connection: dedicated BAT+ and BAT- pins

Control buttons: 4

Dimensions: 45 x 36 mm

Pinout:

Usage:

Copy the MP3 files to a MicroSD card formatted as FAT32 or to a USB flash drive, preferably in the root directory of the storage device.

Insert the card into the TF slot or connect the USB flash drive to the module's USB-A port.

Connect the 2W, 4 Ohm speaker to the two-position screw terminal, or connect an external amplifier or headphones to the 3.5 mm jack.

Power the board at 5VDC via the MicroUSB port or connect a 3.7VDC Li-Ion battery to the BAT+ and BAT- pins, observing polarity.

Briefly press the P / P / Mode button to start or pause playback.

Use a short press on Prev and Next to change tracks and a long press of about 2 seconds to adjust volume.

Press and hold the P / P / Mode button to switch between USB flash drive mode and TF card mode.

Briefly press the Repeat button to choose between repeating the current track and repeating the entire list.

For USB flash drive mode, 5VDC power supply is recommended, since some flash drives do not work properly at 3.7VDC.

For automation, connect the microcontroller's digital pins to the button contacts and simulate presses by switching them to ground, ensuring a common ground between the module and the development board.