DFPlayer - A Mini MP3 Player For Arduino

DFPlayer - A Mini MP3 Player For Arduino https://www.dfrobot.com/index.php?route=product/product&product_id=1121

This example shows the all the function of library for DFPlayer.

Created 2016-12-07 By Angelo qiao

GNU Lesser General Public License. See http://www.gnu.org/licenses/ for details. All above must be included in any redistribution

Notice and Trouble shooting

1.Connection and Diagram can be found here https://www.dfrobot.com/wiki/index.php/DFPlayer_Mini_SKU:DFR0299#Connection_Diagram 2.This code is tested on Arduino Uno, Leonardo, Mega boards.

Updates by Anatoli Arkhipenko

Created an asynchronous version of this library to avoid use of blocking delay methods in the original library, and make it friendly for cooperative multitasking frameworks, like TaskScheduler. Even a 10 ms delay could be problematic for processes that require polling of data at 500Hz for instance (IMUs).

The way the MP3 board works is every method ends up sending a 10 bytes command via 9600 serial pipe. Depending on a microcontroller, this can take up to 12-15 milliseconds. The original library also adds explicit delays to wait for serial operations completion, which are blocking and are strongly discouraged in a cooperative multitasking environment.

The new approach is to utilize availableForWrite() method available in some of the Serial implementations to guarantee a very fast return from the DFPlayerMini methods involving serail communications.

Definition of availableForWrite is: Get the number of bytes (characters) available for writing in the serial buffer without blocking the write operation.

Any time a DFPlayerMini method is called, it returns quickly having written only as many bytes as the target platform can transmit without delay. (E.g., Teensy 3.5 board has a 8 byte long FIFO buffer on Serial1 and Serial2 interfaces). The implementation should call bool DFPlayerMini::commandCompleted() periodically (once every 1 to 10 ms) until it returns true. If commandCompleted() returns false, there is still unsent data in the buffer.

For implementations using TaskScheduler cooperatinve multitasking, an apprach would be to call appropriate player method, and then restart a periodic Task that calls commandCompleted() until that returns true.

If delay is not an issue, OR you need to play a sound in the setup() method when scheduling is not yet active, a new method void DFPlayerMini::completeCommand() could be used to finish transmission synchronously.

Examples:

Player setup:

#include <DFPlayerMini_t3.h> 
DFPlayerMini player;

...

void setupPlayer() {
  Serial.begin(9600);
  delay(100);
  while (!Serial) ;;

  player.begin(Serial, false, true);  // No ACK, reset

  player.setTimeOut(500);
  player.volume(volume);  			    // Set volume value (0~30).
  player.completeCommand();         // Complete synchronously 

  //----Set different EQ----
  player.EQ(DFPLAYER_EQ_NORMAL);
  player.completeCommand();         // Complete synchronously 
  
  //----Set device we use SD as default----
  player.outputDevice(DFPLAYER_DEVICE_SD);
  player.completeCommand();         // Complete synchronously 
}

Asyncronous control with TaskScheduler

#include <TaskScheduler.h>
#include <DFPlayerMini_t3.h> 
DFPlayerMini player;

// Task definition:
Task  tPlayerIterator(10 * TASK_MILLISECOND, TASK_FOREVER, &iterateCallback, &ts, false);

...

  if ( b.cmd == C_PLAY_FILE_ONCE ) {  // play once
    player.playFolder(b.folder, b.file);
    tPlayerIterator.restart();
  }
  
  
void iterateCallback() {
  if ( player.commandCompleted() ) tPlayerIterator.disable();
}