Arduino Nano nRF24L01+ DFPlayer Mini SPI Problem

Question

I'm working with an Arduino Nano board clone (CH340) on wireless control of DFPlayer Mini, transceiver sending a Struct variable with MachinePrefix (just in case), sound type (I have more folders by type of machines) and number of sounds.

The transceiver works fine, but the receiver doesn't. If I upload data into the Arduino, the DFPlayer plays the first song once (row 43 - myDFPlayer.play(1)), but after nRF24 init is not working.

After nRF24 init I'm still receiving data in valid format and range. If I comment out the nRF24 part, the DFPlayer is working, but together not. I read about working two devices on one SPI bus but I don't understand what's wrong. I think the problem is the same MOSI pin. In my opinion it should work but did not.

Any suggestions?

Here is the code of receiver:

#include 
#include "RF24.h"
#include "Arduino.h"
#include "SoftwareSerial.h"
#include "DFRobotDFPlayerMini.h"

RF24 myRadio (8, 9); // CE, CS
byte addresses[][6] = {"Sx001"};

SoftwareSerial mySoftwareSerial(10, 11); // RX, TX
DFRobotDFPlayerMini myDFPlayer;
void printDetail(uint8_t type, int value);

struct dataStruct {
  short machinePrefix;
  short soundType;
  short soundNumber;
} dataReceived;

void setup() {
  mySoftwareSerial.begin(9600);
  Serial.begin(115200);
  delay(1000);
  Serial.println(F("RF24+dfplayermini-recever"));
  Serial.println(F("Initializing DFPlayer ... (May take 3~5 seconds)"));
  if (!myDFPlayer.begin(mySoftwareSerial)) {  //Use softwareSerial to communicate with mp3.
    Serial.println(F("Unable to begin:"));
    Serial.println(F("1.Please recheck the connection!"));
    Serial.println(F("2.Please insert the SD card!"));
    while(true);
  }

  Serial.println(F("DFPlayer Mini online."));
  myDFPlayer.setTimeOut(500);
  myDFPlayer.volume(5);  //Set volume value. From 0 to 30
  myDFPlayer.play(1);  //Play the first mp3
  //----------------------------
  delay(1000);
  myRadio.begin();  // Start up the physical nRF24L01 Radio
  myRadio.setChannel(108);  // Above most Wifi Channels
  // Set the PA Level low to prevent power supply related issues since this is a
  // getting_started sketch, and the likelihood of close proximity of the devices. RF24_PA_MAX is default.
  myRadio.setPALevel(RF24_PA_MAX);
  myRadio.setDataRate(RF24_250KBPS);
  //  myRadio.setPALevel(RF24_PA_MAX);  // Uncomment for more power
  myRadio.openReadingPipe(1, addresses[0]); // Use the first entry in array 'addresses' (Only 1 right now)
  myRadio.startListening();
  Serial.println(F("RF24 online."));
}//--(end setup )---

void loop() {  /****** LOOP ******/
  if (myDFPlayer.available()) {
    printDetail(myDFPlayer.readType(), myDFPlayer.read()); //Print the detail message from DFPlayer to handle different errors and states.
  }
  if (myRadio.available()) { // Check for incoming data from transmitter
    while (myRadio.available()) { // While there is data ready
      myRadio.read( &dataReceived, sizeof(dataReceived) ); // Get the data payload 
    }
    Serial.println("loop");
    myDFPlayer.loop(3);
    if (dataReceived.machinePrefix == 11001) {
      Serial.println("same device prefix");
      int playingData = dataReceived.soundNumber;
      if (myDFPlayer.available()) {
        Serial.println("player available");
        Serial.println(myDFPlayer.readType());
        Serial.println(myDFPlayer.read());
      }
      myDFPlayer.play(2);
    }
    Serial.println(dataReceived.machinePrefix);
    Serial.println(dataReceived.soundType);
    Serial.println(dataReceived.soundNumber);
    Serial.println("-----------------------------");
  } //END Radio available
}//--(end main loop )---

/*----------*/
void printDetail(uint8_t type, int value){
  switch (type) {
    case TimeOut:
      Serial.println(F("Time Out!"));
      break;
    case WrongStack:
      Serial.println(F("Stack Wrong!"));
      break;
    case DFPlayerCardInserted:
      Serial.println(F("Card Inserted!"));
      break;
    case DFPlayerCardRemoved:
      Serial.println(F("Card Removed!"));
      break;
    case DFPlayerCardOnline:
      Serial.println(F("Card Online!"));
      break;
    case DFPlayerPlayFinished:
      Serial.print(F("Number:"));
      Serial.print(value);
      Serial.println(F(" Play Finished!"));
      break;
    case DFPlayerError:
      Serial.print(F("DFPlayerError:"));
      switch (value) {
        case Busy:
          Serial.println(F("Card not found"));
          break;
        case Sleeping:
          Serial.println(F("Sleeping"));
          break;
        case SerialWrongStack:
          Serial.println(F("Get Wrong Stack"));
          break;
        case CheckSumNotMatch:
          Serial.println(F("Check Sum Not Match"));
          break;
        case FileIndexOut:
          Serial.println(F("File Index Out of Bound"));
          break;
        case FileMismatch:
          Serial.println(F("Cannot Find File"));
          break;
        case Advertise:
          Serial.println(F("In Advertise"));
          break;
        default:
          break;
      }
      break;
    default:
      break;
  }
}

Answer 1

When using SPI, pin 10 should never be used as an INPUT. Otherwise the Atmega can go into SPI Slave mode. But you use pin 10 as the RX pin.

Just swap pin 9 and 10, and update your code accordingly.