How to Use DFPlayer Mini Mp3 Player KeeYees: Examples, Pinouts, and Specs

The DFPlayer Mini MP3 Player KeeYees (Part ID: ‎KYES65-KIT) is a compact and versatile MP3 player module designed for audio playback in DIY electronics projects. It supports audio files stored on a micro SD card and features a built-in amplifier, making it ideal for standalone or microcontroller-based applications. The module is compatible with various audio formats, including MP3, WAV, and WMA, and can be controlled via serial communication or standalone mode.

• DIY audio systems and portable speakers
• Voice prompts and sound effects in embedded systems
• Interactive art installations
• Alarm systems with audio notifications
• Educational projects and Arduino-based audio applications

• Operating Voltage: 3.2V to 5.0V DC
• Current Consumption: 20mA to 30mA (idle), up to 100mA (playback)
• Audio Formats Supported: MP3, WAV, WMA
• Storage: Micro SD card (up to 32GB, FAT16/FAT32 file system)
• Output Options:
  • Stereo audio output via DAC pins
  • Mono amplified output via onboard speaker pins
• Control Modes: Serial communication (UART), AD key control, or standalone mode
• Built-in Amplifier: 3W mono output for direct speaker connection
• Dimensions: 22mm x 30mm x 11mm

The DFPlayer Mini has 16 pins, as described in the table below:

1. Power Supply: Connect the VCC pin to a 3.2V–5.0V DC power source and GND to ground.
2. Audio Output:
   • For stereo output, connect DAC_R and DAC_L to an external amplifier or headphones.
   • For mono output, connect SPK_1 and SPK_2 to a speaker (3W max).
3. Microcontroller Connection:
   • Connect the RX pin of the DFPlayer Mini to the TX pin of the microcontroller.
   • Connect the TX pin of the DFPlayer Mini to the RX pin of the microcontroller.
4. Micro SD Card:
   • Format the micro SD card to FAT16 or FAT32.
   • Load audio files onto the card, ensuring filenames are in the format 0001.mp3, 0002.mp3, etc.
   • Insert the card into the SD slot on the module.
5. Control:
   • Use UART serial commands for precise control via a microcontroller.
   • Alternatively, use AD key inputs for standalone operation.

• Ensure the power supply is stable and within the specified voltage range to avoid damage.
• Use a decoupling capacitor (e.g., 100µF) across the VCC and GND pins to reduce noise.
• Avoid connecting both DAC and SPK outputs simultaneously to prevent signal interference.
• Use a resistor divider or level shifter if connecting to a 5V logic microcontroller to protect the RX pin.

Below is an example of how to connect and control the DFPlayer Mini with an Arduino UNO:

• VCC → 5V on Arduino
• GND → GND on Arduino
• RX → Pin 10 on Arduino (via a 1kΩ resistor for level shifting)
• TX → Pin 11 on Arduino

#include "SoftwareSerial.h"

// Define RX and TX pins for SoftwareSerial
SoftwareSerial mySerial(10, 11); // RX, TX

void setup() {
  mySerial.begin(9600); // Initialize DFPlayer Mini communication
  Serial.begin(9600);   // Initialize Serial Monitor for debugging

  // Send initialization commands to DFPlayer Mini
  mySerial.write(0x7E); // Start byte
  mySerial.write(0xFF); // Version
  mySerial.write(0x06); // Length
  mySerial.write(0x09); // Command: Select device
  mySerial.write(0x00); // Feedback
  mySerial.write(0x02); // Parameter: SD card
  mySerial.write(0xEF); // End byte

  Serial.println("DFPlayer Mini initialized.");
}

void loop() {
  // Example: Play the first track
  mySerial.write(0x7E); // Start byte
  mySerial.write(0xFF); // Version
  mySerial.write(0x06); // Length
  mySerial.write(0x03); // Command: Play track
  mySerial.write(0x00); // Feedback
  mySerial.write(0x00); // High byte of track number
  mySerial.write(0x01); // Low byte of track number (Track 1)
  mySerial.write(0xEF); // End byte

  delay(5000); // Wait for 5 seconds before replaying
}

1. No Sound Output:

   • Ensure the micro SD card is properly formatted and inserted.
   • Verify that audio files are named correctly (e.g., 0001.mp3).
   • Check speaker connections and ensure the speaker is within the 3W limit.

2. Module Not Responding:

   • Confirm the power supply voltage is within the 3.2V–5.0V range.
   • Check UART connections and ensure RX/TX pins are correctly wired.
   • Use a level shifter if the microcontroller operates at 5V logic.

3. Playback Stops Unexpectedly:

   • Ensure the micro SD card is not corrupted.
   • Use a high-quality micro SD card with a fast read speed.

4. Distorted Audio:

   • Reduce the volume using UART commands if the speaker is overdriven.
   • Use an external amplifier for better audio quality.

• Can I use the DFPlayer Mini without a microcontroller? Yes, the module supports standalone mode using AD key inputs.

• What is the maximum supported micro SD card size? The module supports micro SD cards up to 32GB formatted as FAT16 or FAT32.

• Can I connect headphones directly to the module? Yes, use the DAC_R and DAC_L pins for stereo headphone output.

• Is the module compatible with 3.3V logic microcontrollers? Yes, the module works with both 3.3V and 5V logic levels.