Simple FM Radio Receiver With Arduino UNO and RDA5807M

In this project, we will use the RDA5807M FM receiver to listen to some local radio stations using an Arduino. Moreover, we will also display the current radio station on an OLED screen.

What is an RDA5807M FM Receiver?

The RDA5807M is a simple stereo radio chip that supports worldwide FM bands from 50MHz to 115MHz. It has a fully integrated synthesizer, (intermediate frequency (IF) selectivity, RDS/RBDS, and an MPX decoder. 

This chip has a powerful low-IF digital audio processor, which means that you can directly listen to the audio via headphones. If you wish to connect it to bigger speakers, however, you might need an audio amplifier circuit. I will be using a simple portable speaker with a built-in audio amplifier for this project. Now let’s get started!

Required Hardware

• Arduino UNO (or any other)
• RDA5807M
• I2C OLED Display
• Radio or TV Antenna 

RDA5807M Pinout

Required Software

• Arduino IDE
• RDA5807M library

Wiring Up the Hardware

Connect the radio receiver (RDA5807M) with the Arduino UNO as shown below. 

You can use a one-foot, single-strand wire as an antenna or a TV/radio antenna for this receiver. Rout (right audio out) and Lout (left audio out) of the RDA5807M module can be connected via a 3.5mm audio jack female connector. For this purpose, you can make an aux cable as I did in the picture below.

Using a breadboard, connect the OLED as shown below and connect the three buttons in series using 10-kiloohm resistors. The buttons are connected to analog pin A0 of the Arduino. The OLED display and FM receiver module share the same SDA and SCL lines with the Arduino.

Once all of the hardware is wired up, here is what your build should look like:

Uploading the Source Code

After double-checking all of the connections, upload the source code by copy-pasting and uploading the code below into Arduino IDE.

        #include <EEPROM.h> 

#include <Wire.h>
#include <SPI.h>
#include <Adafruit_GFX.h>
//#include <TFT_ILI9163C.h>
#include <Adafruit_SSD1306.h>
#include <RDA5807M.h>
#include <RDSParser.h>
#include <radio.h>
//extern const uint8_t icon_radio[];
//extern const uint8_t icon_volume[];
RDA5807M radio;    ///< Create an instance of a RDA5807 chip radio
#define DEBUG 0
#define OLED_RESET 4

Adafruit_SSD1306 tft(OLED_RESET);
RDSParser rds;

enum RADIO_STATE {
  STATE_PARSECOMMAND, ///< waiting for a new command character.
  
  STATE_PARSEINT,     ///< waiting for digits for the parameter.
  STATE_EXEC          ///< executing the command.
};

RADIO_STATE state; ///< The state variable is used for parsing input characters.


const int entrada = A0; 
int entradaV = 0; 

int menu;
#define MAXmenu  3
int menux;
#define MAXmenux  3
static char* menuS[]= {" ","MANUAL TUNE","VOLUME     ","AUTO TUNE","INFO        "};


int volumen, volumenOld=7;
int frecuencia,frecuenciaOld;
int signal_level;

unsigned int z,z1;
byte xfrecu,xfrecuOld;
unsigned int estado[6];

unsigned long time,time1,time2,time3;


char buffer[30];
unsigned int RDS[4];
char seg_RDS[8];
char seg_RDS1[64];
char indexRDS1;

char hora,minuto,grupo,versio;
unsigned long julian;

 int mezcla;
//radio.debugEnable();
void RDS_process(uint16_t block1, uint16_t block2, uint16_t block3, uint16_t block4) {
  rds.processData(block1, block2, block3, block4);
}
void setup() 
{
  Wire.begin();   
  //Serial.begin(9600); 
  Serial.begin(57600);
 tft.begin(SSD1306_SWITCHCAPVCC, 0x3C);
 radio.init();
 radio.debugEnable();
 tft.display();
  delay(20);

  // Clear the buffer.
  tft.clearDisplay();

// read value of last frequency
frecuencia = EEPROM.read(201);
volumen = EEPROM.read(202);

if (volumen < 0) volumen = 0;
if (volumen >15) volumen = 15;
if (frecuencia <0) frecuencia = 0;
if (frecuencia >210) frecuencia = 210;
  
  tft.setRotation(0);
  tft.setTextColor(WHITE);
 
tft.setCursor(95,0);
// tft.print("Nivel semnal :");
  tft.print(signal_level);tft.display();
   tft.print("/15 ");
   // draw an antenna
   tft.drawLine(103, 9, 103, 13, WHITE);
   tft.drawCircle(103,9,2,WHITE);

 
   WriteReg(0x02,0xC00d); // write 0xC00d into Reg.2 ( soft reset, enable,RDS, )
   WriteReg(0x05,0x84d8);  // write ,0x84d8 into Reg.3 
   
  time3=time2=time1=time = millis();
  menu=3;
  
  canal(frecuencia);
 // clearRDS;

  state = STATE_PARSECOMMAND;
 
  // setup the information chain for RDS data.
  radio.attachReceiveRDS(RDS_process);
  rds.attachServicenNameCallback(tftServiceName);
//  rds.attachTimeCallback(tftTime);
}
/*
void tftTime(uint8_t hour, uint8_t minute) {
  tft.setCursor(60, 100); 
  tft.setTextSize(2);    
  tft.setTextColor(GREENYELLOW, BLACK);
  if (hour < 10) tft.print('0');
  if (hour > 30) tft.print(' ');
  tft.print(hour);
  tft.print(':');
  if (minute < 10) tft.print('0');
  tft.println(minute); 
  tft.setTextColor(GREENYELLOW, BLACK);
} // tftTime()
*/
void tftServiceName(char *name)
{
  size_t len = strlen(name);
  tft.setCursor(0, 25);
  tft.setTextSize(1.5);    
  tft.setTextColor(WHITE, BLACK); 
  tft.print(name);tft.setTextColor(WHITE, BLACK);  tft.display();
  while (len < 8) {
    tft.print(' ');tft.setTextColor(WHITE, BLACK); tft.display();
    len++;  
  } // while
} // tftServiceName()
void loop() {
  int newPos;
  unsigned long now = millis();
 // static unsigned long nextFreqTime = 0;
  static unsigned long nextRadioInfoTime = 0;
  char c;
  entradaV = analogRead(entrada);
  
   #if DEBUG  
      Serial.print("sensor = " );  Serial.println(entradaV);delay(50);
   #endif
   
// Boton menu   
 if(entradaV>500 && entradaV<524)
   {
    Serial.print(entradaV);
    menu++;
    if(menu>MAXmenu)menu=1;
    Visualizar();

    #if DEBUG 
      Serial.print("menu = " );  Serial.println(menu); 
    #endif   
    while(1020>analogRead(entrada))delay(5);
   }
            
// Boton derecho
 if( entradaV<50)
   {
    Serial.print(entradaV);
    menux++;
    if(menux>MAXmenux)menux=MAXmenux;
    #if DEBUG 
      Serial.print("menux = " );  Serial.println(menux);
    #endif
    switch(menu)
      {
        case 1:
          frecuencia++;
          if(frecuencia>210)frecuencia=210; // верхняя граница частот
          delay(130);
        break;  
        case 2:
           volumen++;
           if(volumen>15)volumen=15;
           while(1020>analogRead(entrada))delay(5);
        break; 
        case 3:
           busqueda(0);
           while(1020>analogRead(entrada))delay(5);
        break; 
        case 4:
           // LcdClear();
            tft.clearDisplay();
           // visualPI();
            delay(3000);
           // LcdClear();
            tft.clearDisplay();
            frecuenciaOld=-1;
        break; 
      }              
   }
   
// Boton izquierdo
 if( entradaV<700 && entradaV>660)
 //if( entradaV<700 && entradaV>660)
   {
    Serial.print(entradaV);
    menux--;
    if(menux<1)menux=1; 
    #if DEBUG 
      Serial.print("menux = " );  Serial.println(menux);
    #endif   
    switch(menu)
      {
        case 1:
            frecuencia--;
            if(frecuencia<0)frecuencia=0;    
            delay(130);
        break;  
        case 2:
            volumen--;
            if(volumen<0)volumen=0;
            while(1020>analogRead(entrada))delay(5);
        break; 
        case 3:
            busqueda(1);
            while(1020>analogRead(entrada))delay(5);
        break; 
        case 4:
           // LcdClear();
          tft.clearDisplay();
            //tft.print(frecuencia);
            //visualPTY();
            delay(3000);
           // LcdClear();
            tft.clearDisplay();
            frecuenciaOld=-1;
        break; 
      }
    
   }
      
      if( millis()-time2>50)
          {
           ReadEstado();
           time1 = millis(); 
            //RDS   
           if ((estado[0] & 0x8000)!=0) {get_RDS();}
          }
     if( millis()-time3>500)
          {
            time3 = millis();
            Visualizar(); 

          }

    if( frecuencia!=frecuenciaOld)
          {  
            frecuenciaOld=frecuencia;                        
            z=870+frecuencia;
            EEPROM.write(201,frecuencia);
         #if DEBUG  
            Serial.print("Frecuencia = " );  Serial.println(frecuencia);
         #endif 
            sprintf(buffer,"%04d ",z);
  // tft.drawBitmap(80, 2,  icon_volume, 24, 10, WHITE);
  //tft.display();
            tft.setCursor(0,0); 
            tft.setTextSize(2);    
            tft.setTextColor(WHITE, BLACK); 
          for(z=0;z<5;z++)
               {
          if (z==0) {
          if (frecuencia < 130) tft.print(" ");
          else tft.print(buffer[0]);tft.setTextColor(WHITE, BLACK);
          
       
          }
                     
             if(z==3)  tft.print(",");tft.setTextColor(WHITE, BLACK); 
             
           if (z>0) tft.print(buffer[z]);tft.setTextColor(WHITE, BLACK); 
               }
               
               
       //   LcdString("MHz"); 
          tft.setCursor(65,5);
          tft.setTextSize(1);
          tft.setTextColor(WHITE, BLACK);  
          tft.print("MHz");
          tft.setTextColor(WHITE, BLACK); 
           tft.display();
        
          canal(frecuencia);
        //  clearRDS();
       }     

    //Cambio de volumen        
    if(volumen!=volumenOld)
        { 
          volumenOld=volumen;
          sprintf(buffer,"Volum %02d",volumen); tft.setCursor(62,25); tft.setTextSize(1); tft.setTextColor(WHITE, BLACK); tft.print(buffer);tft.print(" ");       
          tft.display();tft.print("/15");
          WriteReg(5, 0x84D0 | volumen);
          EEPROM.write(202,volumen);
        }    
         // check for RDS data
  radio.checkRDS();

  
}


void busqueda(byte direc)
{
  byte i;
  if(!direc) WriteReg(0x02,0xC30d); else  WriteReg(0x02,0xC10d);
  
  for(i=0;i<10;i++)
    {
      delay(200);      
      ReadEstado();      
      if(estado[0]&0x4000)
        {
          //Serial.println("Emisora encontrada");
          frecuencia=estado[0] & 0x03ff;  
          break;
        }       
    }
}

void Visualizar(void)
{ 
     
   //  tft.setCursor(3, 13); tft.setTextSize(2); tft.setTextColor(WHITE, BLACK); tft.print("FM"); 
    // tft.setCursor(27, 20); tft.setTextSize(1); tft.setTextColor(WHITE, BLACK); tft.print("RDA5807-"); 
      sprintf(buffer,"%s",menuS[menu]); tft.setCursor(5,17); tft.setTextSize(1); tft.setTextColor(WHITE,BLACK); tft.print(buffer); 
       //Detectar se&#241;al stereo
       tft.display();
       tft.setCursor(85,15);
       tft.setTextColor(BLACK, WHITE);
       if((estado[0] & 0x0400)==0)  tft.print("");   else     tft.setTextColor(BLACK, WHITE); tft.print("Stereo");  tft.setTextColor(BLACK, WHITE);      
       tft.display();
       //Se&#241;al 
     //  z=estado[1]>>10; sprintf(buffer,"S-%02d",z); tft.setCursor(58,0); tft.setTextColor(WHITE, BLACK); tft.print(buffer); tft.setCursor(25,0);tft.setTextColor(WHITE, BLACK);tft.print("Canal");
      sprintf(buffer,"Volum %02d",volumen); tft.setCursor(62,25);tft.setTextSize(1); tft.setTextColor(WHITE, BLACK); tft.print(buffer); //DUBLARE AFISARE VOLUM
       tft.display();tft.print("/15");
      frecuencia=estado[0] & 0x03ff;  
    
  }

void canal( int canal)
     {
       byte numeroH,numeroL;
       
       numeroH=  canal>>2;
       numeroL = ((canal&3)<<6 | 0x10); 
       Wire.beginTransmission(0x11);
       Wire.write(0x03);
         Wire.write(numeroH);                     // write frequency into bits 15:6, set tune bit         
         Wire.write(numeroL);
         Wire.endTransmission();
       }

//________________________ 
//RDA5807_adrr=0x11;       
// I2C-Address RDA Chip for random      Access
void WriteReg(byte reg,unsigned int valor)
{
  Wire.beginTransmission(0x11);
  Wire.write(reg); Wire.write(valor >> 8); Wire.write(valor & 0xFF);
  Wire.endTransmission();
  //delay(50);
}

//RDA5807_adrs=0x10;
// I2C-Address RDA Chip for sequential  Access
int ReadEstado()
{
 Wire.requestFrom(0x10, 12); 
 for (int i=0; i<6; i++) { estado[i] = 256*Wire.read ()+Wire.read(); }
 Wire.endTransmission();

}

//READ RDS  Direccion 0x11 for random access
void ReadW()
{
  // Wire.beginTransmission(0x11);            // Device 0x11 for random access
  // Wire.write(0x0C);                                // Start at Register 0x0C
  // Wire.endTransmission(0);                         // restart condition
  // Wire.requestFrom(0x11,8, 1);       // Retransmit device address with READ, followed by 8 bytes
  // for (int i=0; i<4; i++) {RDS[i]=256*Wire.read()+Wire.read();}        // Read Data into Array of Unsigned Ints
  // Wire.endTransmission();                  
 } 

 void get_RDS()
 {    
 /* int i;
  ReadW();      
  grupo=(RDS[1]>>12)&0xf;
      if(RDS[1]&0x0800) versio=1; else versio=0;  //Version A=0  Version B=1   
      if(versio==0)
      {
       #if DEBUG             
       sprintf(buffer,"Version=%d  Grupo=%02d ",versio,grupo); Serial.print(buffer);
   
    #endif 
    switch(grupo)
    {
     case 0:              
      #if DEBUG 
      Serial.print("_RDS0__");     
      #endif
      i=(RDS[1] & 3) <<1;
      seg_RDS[i]=(RDS[3]>>8);       
      seg_RDS[i+1]=(RDS[3]&0xFF);
      //tft.setCursor(20,100);tft.setTextColor(BLUE, BLACK); 
      for (i=0;i<8;i++)
      {
        #if DEBUG 
        Serial.write(seg_RDS[i]);   
        #endif
        
       // if(seg_RDS[i]>31 && seg_RDS[i]<128)
      //  tft.print(seg_RDS[i]);
       // else
      //  tft.setTextColor(BLUE, BLACK); 
        //tft.clearScreen();
    
      }  
       
      
      #if DEBUG                 
      Serial.println("---");
      #endif
      break;
     case 2:
      i=(RDS[1] & 15) <<2;              
      seg_RDS1[i]=(RDS[2]>>8);       
      seg_RDS1[i+1]=(RDS[2]&0xFF);
      seg_RDS1[i+2]=(RDS[3]>>8);       
      seg_RDS1[i+3]=(RDS[3]&0xFF);
      #if DEBUG 
      Serial.println("_RADIOTEXTO_");
              
              for (i=0;i<32;i++)  Serial.write(seg_RDS1[i]);                                    
              Serial.println("-TXT-");
              #endif      
              break;
              case 4:             
              i=RDS[3]& 0x003f;
              minuto=(RDS[3]>>6)& 0x003f;
              hora=(RDS[3]>>12)& 0x000f;
              if(RDS[2]&1) hora+=16;
              hora+=i;        
              z=RDS[2]>>1;
              julian=z;
              
              if(RDS[1]&1) julian+=32768;
              if(RDS[1]&2) julian+=65536;
              #if DEBUG 
              Serial.print("_DATE_");
              Serial.print(" Juliano=");Serial.print(julian);
             // sprintf(buffer," %02d:%02d ",hora,minuto); tft.setCursor(50,110); tft.setTextColor(CYAN, BLACK); tft.print(buffer); 
              Serial.println(buffer); 
              #endif            
              break;
              default:
              #if DEBUG 
              Serial.println("__"); 
              #endif    
              ;        
            }                        
          }                   
   */      }
    

Now, tune in to the popular radio stations in your area by clicking the right button. You will be able to see the current FM band on the OLED screen. By default, the receiver will be set to auto-tune.

If the quality of the audio is low, you can also try adjusting your antenna to get a better signal.