The following article was made by the guest author Bastian Brumbi made available:

The aim of this series is to exist Tonuino set to expand some features. To do this, we start with the basic concept of this project. The goal of the first part is that the corresponding MP3 file is played when a card is held and the volume can be set via the three additional buttons, the playback can be paused and the cards can be programmed.

To play the sound files, we need the DFPlayer from the Tonuino Set and a micro SD card (max. 32GB, FAT32) with the files. Here it is important that the files are named with numbers ("001.mp3" or "001Name.mp3") so that the DFPlayer can read them.

Hardware

• The Tonuino set, consisting of aNano, the MFRC522 RFID card reader, the DFPlayer and 10 RFID cards
• Microtre
• Loudspeaker
• If not yet available, a Breadboard with jumper cables  and a 1kotm resistance from the Resistor kit

The components are wired as follows:

software

Next the program, the following libraries must also be installed:

Dfrobot dfplayermini

Mfrc522

These can simply be downloaded as a .zip file and added to Arduino IDE. The libraries can also be installed via the integrated library manager.

Copy or load them The following program In the Arduino Ide, choose the Nano And the right port and upload the program.

If you are the first time with that Nano Working microcontrollers, you must first have the CH340 Install driver

In the upper part of the program, the libraries are integrated and macros for the pins of the microcontroller are defined.

#include <Arduino.h>
#include <Spi.h>
#include <Mfrc522.h>
#include "DfrobotdfPlayermini.h"
#include <Software.h>
 
#define Rst_pin 9
#define Ss_pin 10
#define Up 7
#define OK 6
#define Dwn 5

Now comes the initialization of the objects and variables.

Software softserial(2, 3);
 
Dfrobotdfplayermini mydfplayer;
 
Mfrc522 mfrc522(Ss_pin, Rst_pin);
Mfrc522::Mibare_key key;
Mfrc522::Status code status;
 
byte sector         = 1; // position in the memory
byte blockadr      = 4; 
byte data block[]    = { // buffer to describe
    0x00, 0x00, 0x00, 0x00,
    0x00, 0x00, 0x00, 0x00,
    0x00, 0x00, 0x00, 0x00,
    0x00, 0x00, 0x00, 0x00
};
byte buffer[18]; // buffer for reading
byte trailer block = 7;
Bool State = true;
intimately Filecount = 4; // !!! Number of files, please adjust !!!

The following function is responsible for reading the data from the card. If the serial number of the card cannot be read, it can be concluded that an error in communication with the card has occurred and the function is through a earlyreturn ended prematurely. Then the key is applied and the content of the memory in the array is Buffer written.

void readcard() { // Read the RFID Stack -> Buffer
  IF ( ! mfrc522.Picc_readcarderial())
    return; // card cannot be read -> demolition
 
  byte size = Sizeof(buffer);
  status = (Mfrc522::Status code) mfrc522.PCD_authenticate(Mfrc522::Picc_cmd_mf_auth_key_a, trailer block, &key, &(mfrc522.uid));
  IF (status != Mfrc522::Status_ok) {
    Serial.print(F("PCD_authenticate () Failed:"));
    Serial.print(mfrc522.Get status code name(status));
    return;
  }
  status = (Mfrc522::Status code) mfrc522.MIFARE_READ(blockadr, buffer, &size);
  IF (status != Mfrc522::Status_ok) {
      Serial.print(F("MIFARE_READ () Failed:"));
      Serial.print(mfrc522.Get status code name(status));
  }
  mfrc522.Picc_halta();
  mfrc522.PCD_StopCrypto1();
}

In the method Writecard () Just like the method before a reading error is ended at an early stage. Then the card is authenticated and the array data block written in the memory.

void writecard() { // Writing the DataBlock -> RFID Stack
  IF ( ! mfrc522.Picc_readcarderial())
    return; // card cannot be read -> demolition
 
  status = (Mfrc522::Status code) mfrc522.PCD_authenticate(Mfrc522::Picc_cmd_mf_auth_key_a, trailer block, &key, &(mfrc522.uid));
  IF (status != Mfrc522::Status_ok) {
    Serial.print(F("PCD_authenticate () Failed:"));
    Serial.print(mfrc522.Get status code(status));
    return;
  }
  status = (Mfrc522::Status code) mfrc522.MIFARE_WRITE(blockadr, data block, 16);
  IF (status != Mfrc522::Status_ok) {
      Serial.print(F("MIFARE_WRITE () Failed:"));
      Serial.print(mfrc522.Get status code name(status));
  }
  mfrc522.Picc_halta();
  mfrc522.PCD_StopCrypto1();
}

This next method is carried out when a new card is scanned. In the first step, it is checked whether the marker is present. The marker consists of a 1st position 0 in the memory block 1. If this is not available, it is a new card, to which a file number must first be rewritten. This is implemented by pressing the buttons (select and confirm). If the marker is present, the corresponding file is played.

void startcard() {
  readcard();
  // new card
  IF(buffer[0] != 1) { // marker not available
    mydfplayer.play(1);
    intimately I = 1;
    while(true) {
      IF(!digital read(Up)) {
        while(!digital read(Up)) delay(20);
        IF(I < Filecount) {
          I+=1;
          mydfplayer.next();
        }
        Else {
          I = 1;
          mydfplayer.play(1);
        }
      }
      IF(!digital read(Dwn)) {
        while(!digital read(Dwn)) delay(20);
        IF(I > 1) {
          I-=1;
          mydfplayer.preview();
        }
        Else {
          I = Filecount;
          mydfplayer.play(Filecount);
        }
      }
      IF(!digital read(OK)) { // confirm and describe
        while(!digital read(OK)) delay(20);
        data block[0] = 1;
        data block[1] = I;
        while(!mfrc522.Picc_isnewCardpresent()) delay(20);
        writecard();
        return;
      }
    }
  }
  // registered card
  Else {
    mydfplayer.play(buffer[1]);
  }
}

The function set up() is carried out once after the start. Here the starting functions of the objects are carried out and the key to the memory of the RFID card is written to the associated array.

void set up() {
    softserial.Begin(9600);
    Serial.Begin(115200);
 
  while(!mydfplayer.Begin(softserial, false, false)) {
    Serial.print(F("Undle to Begin"));
    delay(1000);
  }
  
  Spi.Begin();
  mfrc522.PCD_init();
 
  for (byte I = 0; I < 6; I++) {
      key.keybye[I] = 0xff;
  }
  pin mode(Up, Input_pullup);
  pin mode(OK, Input_pullup);
  pin mode(Dwn, Input_pullup);
 
  mydfplayer.volume(5);
}

The Loop () Is the function that after the set up() is constantly repeated. If a new card is recognized, the method becomes Startcard () called. When a button has been pressed, the file is paused or continued, or the volume is changed.

void loop() {
  IF (mfrc522.Picc_isnewCardpresent()) { // Card recognized
    startcard();
  }
  IF(!digital read(Up)) {
    while(!digital read(Up)) delay(20); // Waiting until button was let go
    mydfplayer.volume up();
  }
  IF(!digital read(Dwn)) {
    while(!digital read(Dwn)) delay(20); // Waiting until button was let go
    mydfplayer.volumedown();
  }
  IF(!digital read(OK)) {
    while(!digital read(OK)) delay(20); // Waiting until button was let go
    IF(State) {
      mydfplayer.pause();
      State = 0;
    }
    Else {
      mydfplayer.start();
      State = 1;
    }
  }
}

Service

Next, keep a blank RFID card to the MFRC522 module, then you can select the MP3 file to be played via the outer buttons. The currently selected file is then played. If you have selected the correct file, confirm this by pressing the middle button. Remove the card and hold it again in front of the module. Now the number of the file to be played is saved in the 1kbyte memory of the tag and is played when the card is held again.

If you want to write a new file on the card, you can simply use a free app, such as NFC tools, format (other -> formats memory) and repeat the previous steps.

In the following parts we will expand our previous project with additional functions and modules. Among other things, an OLED display and an LED ring to display the progress, status and names.

Have fun recovery :)