Last Updated: 04/10/2021
Serial UART MP3 player
Components >> Serial UART MP3 player
Serial MP3 Player
The Serial MP3 player, often listed on places like Ebay as Seroal UART MP3/WAV player is a very simple way of being able to play WAV files from an Arduino
It is controlled by sending a series of codes via Serial to the unit.
In these examples I will be using an Arduino UNO so have used the SoftwareSerial library, however with other boards that have multiple Serial ports such as the Arduino Mega 2560 and Arduino Due they can be connected instead.
Serial MP3 Player Issues to consider
The board uses a mini SD card to store the music/sound files. The board does seem to have some issues with read speeds from the SD card, especially if files have been added, eleted and then more files added as the fragmetation seems to cause a slower read speed. I would therefore recommend foratting the card and then copying the files over ni one go.
The player does not recognise filenames so I tend to name my files 01.wav, 02.wav etc and then keep a list of what the files is as most of my files are just sounds that will play on a model railway.
The board plays mono files so if your file is stereo just mix it to mono using a program like Audacity (free download).
Simple Circuit Diagram
Make sure you have the TX and RX connected the right way round
Example 1: UARTSerialV1.ino
Click to Download code:UARTSerialV1.ino
The basics of how the commands work.
/* 28/09/2021
* UARTSerialV1
*
* Simple example of how to play a file with a UART Serial MP3 Player module
*
Serial MP3 Player A | Arduino UNO R3
RX | 3
TX | 4
VCC | 5V
GND | GND
*/
#include
#define ARDUINO_RX 4//should connect to TX of the Serial MP3 Player module
#define ARDUINO_TX 3//connect to RX of the module
SoftwareSerial myMP3(ARDUINO_RX, ARDUINO_TX);
void setup() {
Serial.begin(9600);
Serial.println("UARTSerialV1");
myMP3.begin(9600);
delay(500);//allow everything to settle down
//first we need to select the TF Card
//Manual says the code for this is 7E 03 35 01 EF
myMP3.write(0x7E); //start of instruction
myMP3.write(0x03); //number of bytes excluding start and end byte
myMP3.write(0x35); //Command
myMP3.write(0x01); //data..usually 1 byte
myMP3.write(0xEF); //end byte
delay(20);
Serial.println("Play sound 1");
//Now lets Play the first song 7E 04 41 00 01 EF
myMP3.write(0x7E); //start of instruction
myMP3.write(0x04); //number of bytes excluding start and end byte
myMP3.write(0x41); //command
//next line is the first byte of data 0x00 will mean file is in root directory
myMP3.write((byte)0x00);//forces the value to be read as a byte, otherwise error occurs
myMP3.write(0x01);//will be the first file on the card
myMP3.write(0xEF); //end byte
delay(3000);//wait a second
Serial.println("Play sound 3");
myMP3.write(0x7E); //start of instruction
myMP3.write(0x04); //number of bytes excluding start and end byte
myMP3.write(0x41); //command
//next line is the first byte of data 0x00 will mean file is in root directory
myMP3.write((byte)0x00);//forces the value to be read as a byte, otherwise error occurs
myMP3.write(0x03);//will be the 3rd file on the card
myMP3.write(0xEF); //end byte
}
void loop() {
// put your main code here, to run repeatedly:
}
Example 2: UARTSerialV2.ino
Click to Download code:UARTSerialV2.ino
This script creates some simple functions to control the player
It uses code from the following tutorials:
Lesson 4: Using "for loop" to control code
Lesson 6: Basic Numeric variables, boolean, byte, int, unsigned int, long, unsigned long
Lesson 9: Basic of creating and using functions
/* 28//09/2021
* UARTSerialV2
*
* Creating some useful functions
*
Serial MP3 Player A | Arduino UNO R3
RX | 3
TX | 4
VCC | 5V
GND | GND
*/
#include
#define ARDUINO_RX 4//should connect to TX of the Serial MP3 Player module
#define ARDUINO_TX 3//connect to RX of the module
SoftwareSerial myMP3(ARDUINO_RX, ARDUINO_TX);
byte sendBuffer[6]; //buffer that will be used to store commands before sending
//Manual says the code for this is 7E 03 35 01 EF so load into buffer array
void selectTFCard(){
sendBuffer[0] = 0x7E;
sendBuffer[1] = 0x03;
sendBuffer[2] = 0x35;
sendBuffer[3] = 0x01;
sendBuffer[4] = 0xEF;
sendUARTCommand();
}
void playSound(byte songNumber){
sendBuffer[0] = 0x7E;
sendBuffer[1] = 0x04;
sendBuffer[2] = 0x41;
sendBuffer[3] = 0x00;
sendBuffer[4] = songNumber;
sendBuffer[5] = 0xEF;
sendUARTCommand();
}
//play a sound at a set volume, only seems to apply to root directory files
void playSoundAtVolume(byte volume,byte songNumber){
sendBuffer[0] = 0x7E;
sendBuffer[1] = 0x04;
sendBuffer[2] = 0x31;
sendBuffer[3] = volume;
sendBuffer[4] = songNumber;
sendBuffer[5] = 0xEF;
sendUARTCommand();
}
//
//set the playback volume 7E 03 31 0F EF = set volume to 0x0F = 15
void setplayVolume(byte volume){
sendBuffer[0] = 0x7E;
sendBuffer[1] = 0x03;
sendBuffer[2] = 0x31;
sendBuffer[3] = volume;
sendBuffer[4] = 0xEF;
sendUARTCommand();
}
//stop the current track playing
void stopSound(){
sendBuffer[0] = 0x7E;
sendBuffer[1] = 0x02;
sendBuffer[2] = 0x0E;
sendBuffer[3] = 0xEF;
sendUARTCommand();
}
void sendUARTCommand(){
int q;
for(q=0;q < sendBuffer[1] + 2;q++){
myMP3.write(sendBuffer[q]);
}
Serial.println("Commands Sent");
for(q=0;q < sendBuffer[1] + 2;q++){
Serial.println(sendBuffer[q],HEX);
}
delay(25);//stops odd commands being missed
}
void setup() {
Serial.begin(9600);
Serial.println("UARTSerialV2");
myMP3.begin(9600);
delay(500);//allow everything to settle down
//first we need to select the TF Card
selectTFCard();
}
void loop() {
int q;
/*
//play through the first 5 tracks on the card
for(q=0;q<5;q++){
playSound(q);
delay(4000);
stopSound();
}
*/
/*
//Change the volume and then play track 4
for(q=0;q<30;q++){
setplayVolume(q);//change volume
playSound(4);//play track 4
delay(2000);
stopSound();
}
*/
////Play track 4 with pre set volumes
for(q=0;q<60;q +=10){//volume incremented in steps of 10
playSoundAtVolume(q, 4);//play track 4 at increasing volumes (q)
delay(2000);
stopSound();
}
}
Example 3: UARTSerialV3.ino
Click to Download code:UARTSerialV3.ino
In this example we add a couple of buttons to trigger sounds.
It uses code from the following tutorials:
Lesson 3: Using "if else" to control code
Lesson 7: delay() v's millis(), controlling timing of programs
1k Ohm resistor
/* 28//09/2021
* UARTSerialV3
*
* Sounds with buttons
*
Serial MP3 Player A | Arduino UNO R3
RX | 3
TX | 4
VCC | 5V
GND | GND
Buttons on digital pins 8 & 9
*/
#include
#define ARDUINO_RX 4//should connect to TX of the Serial MP3 Player module
#define ARDUINO_TX 3//connect to RX of the module
SoftwareSerial myMP3(ARDUINO_RX, ARDUINO_TX);
const int buttonOne = 8;
const int buttonTwo = 9;
unsigned long buttonDebounce;
byte sendBuffer[6]; //buffer that will be used to store commands before sending
//Manual says the code for this is 7E 03 35 01 EF so load into buffer array
void selectTFCard(){
sendBuffer[0] = 0x7E;
sendBuffer[1] = 0x03;
sendBuffer[2] = 0x35;
sendBuffer[3] = 0x01;
sendBuffer[4] = 0xEF;
sendUARTCommand();
}
void playSound(byte songNumber){
sendBuffer[0] = 0x7E;
sendBuffer[1] = 0x04;
sendBuffer[2] = 0x41;
sendBuffer[3] = 0x00;
sendBuffer[4] = songNumber;
sendBuffer[5] = 0xEF;
sendUARTCommand();
}
//play a sound at a set volume, only seems to apply to root directory files
void playSoundAtVolume(byte volume,byte songNumber){
sendBuffer[0] = 0x7E;
sendBuffer[1] = 0x04;
sendBuffer[2] = 0x31;
sendBuffer[3] = volume;
sendBuffer[4] = songNumber;
sendBuffer[5] = 0xEF;
sendUARTCommand();
}
//
//set the playback volume 7E 03 31 0F EF = set volume to 0x0F = 15
void setplayVolume(byte volume){
sendBuffer[0] = 0x7E;
sendBuffer[1] = 0x03;
sendBuffer[2] = 0x31;
sendBuffer[3] = volume;
sendBuffer[4] = 0xEF;
sendUARTCommand();
}
//stop the current track playing
void stopSound(){
sendBuffer[0] = 0x7E;
sendBuffer[1] = 0x02;
sendBuffer[2] = 0x0E;
sendBuffer[3] = 0xEF;
sendUARTCommand();
}
void sendUARTCommand(){
int q;
for(q=0;q < sendBuffer[1] + 2;q++){
myMP3.write(sendBuffer[q]);
}
Serial.println("Commands Sent");
for(q=0;q < sendBuffer[1] + 2;q++){
Serial.println(sendBuffer[q],HEX);
}
delay(25);//stops odd commands being missed
}
void setup() {
Serial.begin(9600);
Serial.println("UARTSerialV3");
myMP3.begin(9600);
delay(500);//allow everything to settle down
//first we need to select the TF Card
selectTFCard();
pinMode(buttonOne,INPUT);
pinMode(buttonTwo,INPUT);
}
void loop() {
int buttonPressed;
if(millis() > buttonDebounce){
buttonPressed = digitalRead(buttonOne);
if(buttonPressed > 0){
buttonDebounce = millis() + 200;
stopSound();//stop any existing sounds
playSoundAtVolume(15, 1);//play sound at volume 15, track 1...drill
}
}
if(millis() > buttonDebounce){
buttonPressed = digitalRead(buttonTwo);
if(buttonPressed > 0){
buttonDebounce = millis() + 200;
stopSound();//stop any existing sounds
playSoundAtVolume(25, 3);//play sound at volume 25, track 3...welder
}
}
}
Example 4: UARTSerialV5.ino
This version has an extra function repeatSound() that loops the same track until another track is played
Click to Download code:UARTSerialV5.ino
/* 30/09/2021
* UARTSerialV5
*
* Added an extra function repeatSound() that loops a trackCreating some useful functions
*
Serial MP3 Player A | Arduino UNO R3
RX | 3
TX | 4
VCC | 5V
GND | GND
*/
#include
#define ARDUINO_RX 4//should connect to TX of the Serial MP3 Player module
#define ARDUINO_TX 3//connect to RX of the module
SoftwareSerial myMP3(ARDUINO_RX, ARDUINO_TX);
byte sendBuffer[6]; //buffer that will be used to store commands before sending
//Manual says the code for this is 7E 03 35 01 EF so load into buffer array
void selectTFCard(){
sendBuffer[0] = 0x7E;
sendBuffer[1] = 0x03;
sendBuffer[2] = 0x35;
sendBuffer[3] = 0x01;
sendBuffer[4] = 0xEF;
sendUARTCommand();
}
void playSound(byte songNumber){
sendBuffer[0] = 0x7E;
sendBuffer[1] = 0x04;
sendBuffer[2] = 0x41;
sendBuffer[3] = 0x00;
sendBuffer[4] = songNumber;
sendBuffer[5] = 0xEF;
sendUARTCommand();
}
//play a sound at a set volume, only seems to apply to root directory files
void playSoundAtVolume(byte volume,byte songNumber){
sendBuffer[0] = 0x7E;
sendBuffer[1] = 0x04;
sendBuffer[2] = 0x31;
sendBuffer[3] = volume;
sendBuffer[4] = songNumber;
sendBuffer[5] = 0xEF;
sendUARTCommand();
}
//loop sound 7E 04 33 00 01 EF
void repeatSound(byte songNumber){
sendBuffer[0] = 0x7E;
sendBuffer[1] = 0x04;
sendBuffer[2] = 0x33;
sendBuffer[3] = 0x00;
sendBuffer[4] = songNumber;
sendBuffer[5] = 0xEF;
sendUARTCommand();
}
//set the playback volume 7E 03 31 0F EF = set volume to 0x0F = 15
void setplayVolume(byte volume){
sendBuffer[0] = 0x7E;
sendBuffer[1] = 0x03;
sendBuffer[2] = 0x31;
sendBuffer[3] = volume;
sendBuffer[4] = 0xEF;
sendUARTCommand();
}
//stop the current track playing
void stopSound(){
sendBuffer[0] = 0x7E;
sendBuffer[1] = 0x02;
sendBuffer[2] = 0x0E;
sendBuffer[3] = 0xEF;
sendUARTCommand();
}
void sendUARTCommand(){
int q;
for(q=0;q < sendBuffer[1] + 2;q++){
myMP3.write(sendBuffer[q]);
}
Serial.println("Commands Sent");
for(q=0;q < sendBuffer[1] + 2;q++){
Serial.println(sendBuffer[q],HEX);
}
delay(25);//stops odd commands being missed
}
void setup() {
Serial.begin(9600);
Serial.println("UARTSerialV5");
myMP3.begin(9600);
delay(500);//allow everything to settle down
//first we need to select the TF Card
selectTFCard();
delay(100);
//new function to repeat the same track
repeatSound(12);//repeat sound 12
}
void loop() {
// int q;
/*
//play through the first 5 tracks on the card
for(q=0;q<15;q++){
playSound(q);
delay(4000);
stopSound();
}
*/
/*
//Change the volume and then play track 4
for(q=0;q<30;q++){
setplayVolume(q);//change volume
playSound(4);//play track 4
delay(2000);
stopSound();
}
*/
/*
////Play track 4 with pre set volumes
for(q=0;q<60;q +=10){//volume incremented in steps of 10
playSoundAtVolume(q, 4);//play track 4 at increasing volumes (q)
delay(2000);
stopSound();
}
*/
}
Additional Resource Links
Alternate Sample Serial MP3 sketch
Serial MP3 player manual with all functions listed (PDF format).
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