Figurine Music Box

Concept

Inspired by Skylanders and their Portal of Power, I wanted to make a music box where you put a figurine(typically from a video game) on top, and that character's theme will start playing.

Electronics

This project plans to use the same technology as the Skylanders series: NFC tags and readers. NFC-or Near-Field Communication-tags do exactly as they are labelled to do: when near an NFC reader, the reader will pick up the data that is loaded onto the tag. Using the NFC Tools App or any similar application for a mobile device, I can write a string of numbers(I will explain why I am using numbers soon) to an NFC chip that when read by the NFC reader, will play the song with the corresponding number. Along with this, I have an Arduino Uno R3 to process and send information, a breadboard for connecting wires, a cheap speaker, and a DFPlayer Mini to play songs from the loaded micro sd card to the speaker. The DFPlayer Mini requires you follow a file naming structure that uses three digits(000 to 999). So by writing "003" onto a chip and placing it near the reader, the mp3 file titled "003.mp3" assuming there is such an audio file.

Coding

If you want to skip the explanation of the code and just copy it for your own use, here it is:

          #include 
          #include 
          #include 
          #include 

          #define PN532_IRQ   2
          #define PN532_RESET 3
          Adafruit_PN532 nfc(PN532_IRQ, PN532_RESET);

          SoftwareSerial mySoftwareSerial(10,11);
          DFRobotDFPlayerMini myDFPlayer;

          int currentSong = -1;

          void setup(void) {
            delay(5000);
            Wire.begin();
            Serial.begin(9600);
            mySoftwareSerial.begin(9600);
            delay(1000);

            if (!myDFPlayer.begin(mySoftwareSerial)){
              Serial.println("DFPlayer not found");
              while(true){}
            }
            myDFPlayer.volume(15);

            Serial.println("Looking for PN532...");

            nfc.begin();

            uint32_t versiondata = nfc.getFirmwareVersion();
            if (!versiondata) {
              Serial.println("Didn't find PN532 board");
              while (True);
            }

            Serial.print("Found PN532 with firmware version: ");
            Serial.print((versiondata >> 24) & 0xFF, HEX);
            Serial.print('.');
            Serial.println((versiondata >> 16) & 0xFF, HEX);

            nfc.SAMConfig();
            Serial.println("Waiting for NFC card...");
          }

          void loop(void) {
            int status = myDFPlayer.readState();
            Serial.println(status);
            uint8_t uid[7];
            uint8_t uidLength;

            if (nfc.readPassiveTargetID(PN532_MIFARE_ISO14443A, uid, &uidLength)) {
              uint8_t raw[48]; // 12 pages * 4 bytes per page
              for (uint8_t page = 4; page <= 15; page++) {
                uint8_t buffer[4];
                if (!nfc.ntag2xx_ReadPage(page, buffer)) {
                  Serial.print("Failed to read page "); Serial.println(page);
                  myDFPlayer.pause();
                  currentSong = -1;
                  return;
                }
                memcpy(raw + (page - 4) * 4, buffer, 4);
              } 

              if (raw[0] == 0x03) {
                uint8_t ndefLength = raw[1];
                uint8_t tnfHeader = raw[2];   // Should be 0xD1 for a short text record
                uint8_t typeLength = raw[3];  // Usually 1
                uint8_t payloadLength = raw[4]; // Length of the text + language code
                uint8_t langLength = raw[6];  // e.g., 0x02 = "en"
                uint8_t textStart = 7 + langLength;

                uint8_t textLength = payloadLength - langLength;
                String nfcText = "";
                delay(100);
                for (uint8_t i = textStart; i < textStart + textLength - 1; i++) {
                  nfcText.concat((char)raw[i]);
                }
                Serial.println(nfcText);
                playSong(nfcText);
                Serial.println();
              } else {
                Serial.println("No NDEF message found.");
              }
            }
            delay(50);
          }

          void playSong(String songID){
            songID.trim();
            if(currentSong != songID.toInt()){
              currentSong = songID.toInt();
              Serial.print("Playing track: ");
              Serial.println(currentSong);
              myDFPlayer.play(currentSong);
              myDFPlayer.enableLoop();
            }
  
            delay(500);
          }