Arduino/Genuino Shield WACHARA 1 • วัชระ ๑

A Multiband Receiver based on the TEA5767, for the Arduino DUE, sometimes also referred to as "RADIO-DINO"

In memoriam Khwankeo Vajarodaya, *03.09.1928 †28.01.2017

This shield makes a fully functional fm receiver with the TEA5767 board from funk-amateur. The device has a built-in af power amplifier to drive an internal loudspeaker. It can also be used with an external headset or external speakers.

✈ Functional Description

The signal is coupled in through the sma connector (ANT1) on the left. It is then routed to the board with the TEA5767 chip. This board is available from many sources, we got it from www.box73.de
This board does the most of the work. You can program it via I2C or SPI. We used SPI, here.

The left and right audio signal is then fed into an amplifier with digital volume control. (LM4811). You can program gains from −33dB to +12dB in 16 steps.

The now amplified audio signal can be output via a 3.5 mm stereo jack or, if that is not used, an internal amplifier (LM386) amplifies it to drive the internal speaker. (Mono only).

Please note : As we use a 32.768 kHz crystal here, the grid steps are a multiple of that.
In our case this is 98.304 kHz (3 * 32'768 Hz). You mayst want to round the displayed figues.

The unpopulated pcb, visualisation by Beta Layout

✈ Inside the TEA5767

Picture shows building blocks inside the TEA5767 - courtesy of NXP Semiconductor

"The TEA5767HN is a single-chip electronically tuned FM stereo radio for low-voltage applications with fully integrated Intermediate Frequency (IF) selectivity and demodulation. The radio is completely adjustment-free and only requires a minimum of small and low cost external components. The radio can be tuned to the European, US, and Japanese FM bands." Says the datasheet.

To achieve that, it has an integrated low noise amplifier at the input. The gain of the LNA is controlled by an AGC with a range of 40 dB. It will start to work at an input level of approx. 4 mV. A 4-Bit ADC allows for RSSI measurements in 3 dB steps.

Following the LNA is an IQ mixer. It produces two output signals which are 90° apart. Ideallically, this is suited to suppress the image. Practically it will have a limited image rejection.

The VCO is running at twice the frequency. It covers a range of 150 - 217 MHz. By dividing it down, two LO signals - which are 90° apart - are created and fed into the mixer.

Following is the IF filter. This is a fully integrated bandpass with a center frequency of 225 kHz and a bandwidth of 90 kHz. At 200 kHz from the centre frequency, the selectivity is approx 40 dB.

Following is the limiting amplifier as well as the FM demodulator. The IF is routed to a counter with a prescaler :64. By that, the chip knows if the tuning is below or above the desired radio station. With a gate-time of 15.625 ms the target value is 55 pulses (0x37) for correct tuning.



Counter Results depending on Tuning and gate-time. For a 32.768 kHz crystal, XTAL = 1

✈ Operation • Manual

✈ Inside the Aluminium Case

A look inside

Inside the aluminium case are the usual supects. On the left side, there is an Arduino Due with the Shield "Wachara 1" stacked on top. On the right side, there is a rotary encoder, an oled and the bnc input jack. In the rear, you see the cover with the loudspeaker attached.

✈ Downloads

✈ Arduino Sketch - The Code

Double click on code to select ...

/* ///////////////////////////////////////////////////////////////////// 
ARDUINO/Genuino DUE Sketch for "Wachara 1"
https://www.changpuak.ch/electronics/Arduino-Shield-WACHARA1.php
As Wachara 1 passed away already, we use a white display
"Wachara 1" was the callsign of H.E. Khwankeo Vajarodaya, 
*03.09.1928 †28.01.2017, my teacher for Siamese Culture and Art
Software Version 3.9, 
03.09.2019, Alexander Sse Frank, 
//////////////////////////////////////////////////////////////////////*/


// /////////////////////////////////////////////////////
// Includes
// /////////////////////////////////////////////////////


#include <Adafruit_GFX.h>
#include <Adafruit_SH1106.h>

// OLED 128x64 with SH1106 Controller
// from https://www.displaymodule.com/
// E.G. DM-OLED13-625
#define OLED_MOSI  10
#define OLED_CLK   9
#define OLED_DC    12
#define OLED_CS    13
#define OLED_RESET 11
Adafruit_SH1106 display(OLED_MOSI, OLED_CLK, OLED_DC, OLED_RESET, OLED_CS);

#if (SH1106_LCDHEIGHT != 64)
#error("Height incorrect, please fix Adafruit_SH1106.h!");
#endif


int CURSOR = 2 ;

float RX_FREQ = 107.6 ;    // Radio Basilisk <3
// float freq = 102.50 ;   // Surf 102.5 FM Hua Hin
float freq = 91.25 ;       // KCS Radio Hua Hin
long int pll ;

int MAX_BAR_LENGTH = 45 ;
int MIN_BAR_LENGTH = 1 ;
float MULTI = 2.9 ;

// /////////////////////////////////////////////////////
// LM4811
// /////////////////////////////////////////////////////
int VolUpDownPin = A0 ;
int VolClkPin = A2 ;
int VolShutDownPin = A1 ;

int VOLUME = 0 ;
int SETVOL = 9 ;          
int VOLMIN = 0 ;
int VOLMAX = 15 ;     // 16 STEPS

// /////////////////////////////////////////////////////
// TEA 5767
// /////////////////////////////////////////////////////
const int BusMode = A5 ;
const int WriteRead = A4 ;
const int CursorX = 115 ;
const byte TEA5767_ADR = 0x60 ;
byte RAM[] = {0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00} ;
float BandStart = 87.5 ;
float BandStop = 108.0 ;
int RX_CLK_PIN = 21 ;
int RX_DAT_PIN = 20 ;
// /////////////////////////////////////////////////////
// WRITE
// /////////////////////////////////////////////////////
int HLSI  = 1 ;   // High Side Injection
int MUTE = 0 ;    // L+R UNMUTED
int SM = 0 ;      // NOT IN SEARCH MODE
int SUD = 1 ;     // SEARCH UP
int SSL = 1 ;     // SEARCH STOP LEVEL = LOW ADC output = 5
int MS = 0 ;      // STEREO
int MR = 0 ;      // RIGHT CHANNEL UNMUTED
int ML = 0 ;      // LEFT CHANNEL UNMUTED
int BL = 0 ;      // BAND LIMITS EUROPE
int XTAL = 1 ;    // 32.768 kHz 
int SMUTE = 1 ;   // SOFT MUTE IS ON
int HCC = 0 ;     // HIGH CUT CONTROL IS OFF
int SNC = 1 ;     // STEREO NOISE CANCELLING IS ON
int DTC = 0 ;     //  de-emphasis time constant is 50 µs
// /////////////////////////////////////////////////////
// READ
// /////////////////////////////////////////////////////
int RF = 0 ;
int BLF = 0 ;
int Stereo = 0 ;
int RSSI = 0 ;
int IFCounts = 0 ;


volatile boolean SearchMode = false ;



// ////////////////////////////////////////////////////////////////////
// ROTARY ENCODER
// ////////////////////////////////////////////////////////////////////

const int KEY1 = 6 ;
const int KEY2 = 7 ;
const int KEY3 = 5 ;    // PRESSED

volatile boolean action = false ;
volatile boolean pressed = false ;
volatile boolean clockwise = false ;
volatile boolean rotation = false ;

unsigned int ShortLongPressTime = 199 ; // MILLISECONDS
// IF THE KNOB WAS PRESSED SHORTER, IT IS CONSIDERED "SHORT"
// IF THE KNOB WAS PRESSED LONGER, IT IS CONSIDERED "LONG"
boolean LongPress = false ;

void ISR_K1 (void)
{
  byte autre = digitalRead(KEY2) ;
  if (autre == 1) clockwise = true ;
  else clockwise = false ;
  action = true ;
  pressed = false ;
  rotation = true ;
}

void ISR_K2 (void)
{
  byte autre = digitalRead(KEY1) ;
  if (autre == 1) clockwise = true ;
  else clockwise = false ;
  action = true ;
  pressed = false ;
  rotation = true ;
}

void ISR_K3 (void)
{
  pressed = true ;
  action = true ;
  rotation = false ;
}


// ////////////////////////////////////////////////////////////////////

byte HIBYTE(unsigned int data) 
{
  return ((data & 0xFF00) >> 8) ;
}

// ////////////////////////////////////////////////////////////////////

byte LOBYTE(unsigned int data) 
{
  return (data & 0x00FF) ;
}

// ////////////////////////////////////////////////////////////////////

void VolumeUp(int HowMuch) 
{
  digitalWrite(VolUpDownPin, HIGH);
  for(int i=0; i < HowMuch; i++)
  {
    VOLUME += 1 ;
    digitalWrite(VolClkPin, HIGH);
    delay(100) ;
    digitalWrite(VolClkPin, LOW);
    delay(100) ;
    UpdateOLED() ;
  }
}

// ////////////////////////////////////////////////////////////////////

void VolumeDown(int HowMuch) 
{
  digitalWrite(VolUpDownPin, LOW);
  for(int i=0; i < HowMuch; i++)
  {
    digitalWrite(VolClkPin, HIGH);
    digitalWrite(VolClkPin, LOW);
  }
  VOLUME = 0 ;
  UpdateOLED() ;
}
// ////////////////////////////////////////////////////////////////////

void SET_VOLUME() 
{
  digitalWrite(VolUpDownPin, LOW);
  for(int i=0; i < 18; i++)
  {
    digitalWrite(VolClkPin, HIGH);
    digitalWrite(VolClkPin, LOW);
  }
  digitalWrite(VolUpDownPin, HIGH);
  for(int i=0; i < VOLUME; i++)
  {
    digitalWrite(VolClkPin, HIGH);
    digitalWrite(VolClkPin, LOW);
  }  
  UpdateOLED() ;
}

// ////////////////////////////////////////////////////////////////////

void VolumeMute() 
{
  digitalWrite(VolShutDownPin, HIGH);
}

// ////////////////////////////////////////////////////////////////////

void VolumeUnMute() 
{
  digitalWrite(VolShutDownPin, LOW);
}

// ////////////////////////////////////////////////////////////////////

void setup() 
{
  // TEA5767
  pinMode(BusMode, OUTPUT);
  digitalWrite(BusMode, HIGH);
  pinMode(RX_DAT_PIN, OUTPUT);
  digitalWrite(RX_DAT_PIN, LOW);
  pinMode(RX_CLK_PIN, OUTPUT);
  digitalWrite(RX_CLK_PIN, LOW);
  pinMode(WriteRead, OUTPUT);
  digitalWrite(WriteRead, HIGH);

  // LMX4811
  pinMode(VolUpDownPin, OUTPUT);
  digitalWrite(VolUpDownPin, LOW); // JUST TO HAVE A DEFINED LEVEL
  pinMode(VolClkPin, OUTPUT);
  digitalWrite(VolClkPin, LOW);
  pinMode(VolShutDownPin, OUTPUT);
  digitalWrite(VolShutDownPin, LOW); // SWITCH THAT THING ON
  // This shutdown function is activated by applying a logic high 
  // to the SHUTDOWN pin.
    
  Serial.begin(9600);    // SERIAL
 
  // INIT OLED  
  display.begin(SH1106_SWITCHCAPVCC);
  
  // SHOW STARTUP SCREEN
  display.clearDisplay();
  display.drawLine(0, 14, 128, 14, WHITE);
  display.setTextSize(1);
  display.setTextColor(WHITE);
  display.setCursor(0,0); display.print("****") ;
  display.setCursor(33,0); display.print("WACHARAMOD") ;
  display.setCursor(104,0); display.print("****") ;
  display.setTextSize(1);
  display.setCursor(0,21);
  display.println("A MULTIBAND RECEIVER");
  display.setCursor(0,33);
  display.println("WITH NXP's TEA5767");
  display.setCursor(0,45);
  display.println("IN MEMORIAM WACHARA 1");
  display.setCursor(0,57);
  display.println("BUILT 03.09.2019");
  display.display();
  delay(4999) ;

  VolumeDown(18) ; // YES, WE USE THE COMMODORE 1541 APPROACH HERE
  
  // FREQ_TEA5767(freq) ;
  HiLoOptimiser() ;

  delay(100) ;

  // FREQ_TEA5767(freq) ;
  HiLoOptimiser() ;

  
  Serial.println("TEA5767 RADIO, TYPE WACHARA 1");
  Serial.println("-----------------------------");  
  READ_TEA5767() ;
  Serial.println(RAM[0],HEX) ;   
  Serial.println(RAM[1],HEX) ;   
  Serial.println(RAM[2],HEX) ;   
  Serial.println(RAM[3],HEX) ;   
  Serial.println(RAM[4],HEX) ;   
  Serial.println("-----------------------------");
  
  VOLUME = SETVOL ;
  SET_VOLUME() ; 

  UpdateOLED() ;
 
  // ROTARY ENCODER
  pinMode(KEY1, INPUT_PULLUP) ;
  pinMode(KEY2, INPUT_PULLUP) ;
  pinMode(KEY3, INPUT_PULLUP) ;

  // INTERRUPTS ROTARY ENCODER
  attachInterrupt(digitalPinToInterrupt(KEY1), ISR_K1, RISING);   // ROT 
  attachInterrupt(digitalPinToInterrupt(KEY2), ISR_K2, FALLING);  // ROT
  attachInterrupt(digitalPinToInterrupt(KEY3), ISR_K3, FALLING);  // PRESS
  
  delay(3999);

  action = false ;
  pressed = false ;
  clockwise = false ;
  rotation = false ;

  // SCAN() ;
  freq = 91.25 ;
  HiLoOptimiser() ;


}

// ////////////////////////////////////////////////////////////////////

void BAR(int x, int y, int value) 
{
  if (value > MAX_BAR_LENGTH) value = MAX_BAR_LENGTH ;
  if (value < MIN_BAR_LENGTH) value = MIN_BAR_LENGTH ;
  display.drawRect(x, y, MAX_BAR_LENGTH, 7, WHITE);
  display.fillRect(x, y, value, 7, WHITE);
}


// ////////////////////////////////////////////////////////////////////


void UpdateOLED() 
{
  display.clearDisplay();
  display.drawLine(0, 11, 128, 11, WHITE);
  display.drawLine(0, 32, 128, 32, WHITE);
  display.setTextSize(1);
  display.setTextColor(WHITE);
  display.setCursor(0,0); display.print("****") ;
  display.setCursor(33,0); display.print("WACHARAMOD") ;
  display.setCursor(104,0); display.print("****") ;
  display.setTextSize(2);
  display.setCursor(0,15);
  if(!SearchMode)
  {
  if (freq < 100.0) display.print(" ");
  if (freq < 10.0) display.print(" ");
  display.print(freq,3);
  // display.print("0");
  // CURSOR 
  if (CURSOR == 0) { display.setCursor( 0,19); display.print("_") ; }
  if (CURSOR == 1) { display.setCursor(12,19); display.print("_") ; }
  if (CURSOR == 2) { display.setCursor(24,19); display.print("_") ; }
  if (CURSOR == 3) { display.setCursor(48,19); display.print("_") ; }
  if (CURSOR == 4) { display.setCursor(60,19); display.print("_") ; }
  display.setCursor(92,15);
  display.print("MHz");
  }
  if(SearchMode)
  {
  display.setCursor(10,15);
  display.print("SEARCHING");
  }
  display.setTextSize(1);
  display.setCursor(0,37);
  display.print("RSSI "); 
  if(HLSI == 1) display.print("+"); 
  if(HLSI == 0) display.print("-");
  BAR(40, 37, (RSSI*3) ) ;  
  display.setCursor(91,37);
  if (Stereo == 1) display.print("STEREO");
  if (Stereo == 0) display.print("  MONO");  
  display.setCursor(0,47);
  display.print("VOLUME "); BAR(40, 47, (VOLUME*3) ) ; 
  if (CURSOR == 5) { display.setCursor(91,47); display.print("<<<") ; }
  display.setCursor(0,57);
  display.print("PRESS LONG TO SEARCH"); 
  
  display.display();
}


void ButtonPressed()
{
  // //////////////////////////////////////////////////
  // WAS IT PRESSED LONG >>> START SEARCH UP
  // //////////////////////////////////////////////////
  LongPress = false ;
  delay(ShortLongPressTime) ;
  if(digitalRead(KEY3) == 0) LongPress = true ;
  
  if(LongPress)
  {  
  // //////////////////////////////////////////////////
  // SEARCH UPWARDS
  // //////////////////////////////////////////////////
  Serial.println("PRESSED LONG") ; 
  SearchUP() ;
  pressed = false ;
  
  
  }
  // //////////////////////////////////////////////////
  // WAS IT PRESSED SHORT >>> MOVE CURSOR RIGHT
  // //////////////////////////////////////////////////
  if(!LongPress)
  {  
  Serial.println("PRESSED SHORT") ; 
  CURSOR += 1 ;
  if(CURSOR > 5) CURSOR = 2 ;
  }  
  pressed = false ;
}


void ButtonRotated()
{
  // //////////////////////////////////////////////////
  // WAS IT ROTATED RIGHT >>> INCREASE
  // //////////////////////////////////////////////////
  if(clockwise)
  {
  // Serial.println("CW") ; 
  switch(CURSOR)
  {
    case 2: 
      freq = freq - 1.0 ; 
      if(freq < BandStart) freq = BandStart ;
      HiLoOptimiser() ;
      delay(10) ;
      READ_TEA5767() ;  // RSSI
       break ;
    case 3: 
      freq = freq - 0.1 ; 
      if(freq < BandStart) freq = BandStart ;
      HiLoOptimiser() ;
      delay(10) ;
      READ_TEA5767() ;  // RSSI
      break ;
    case 4: 
      freq = freq - 0.01 ;
      if(freq < BandStart) freq = BandStart ; 
      HiLoOptimiser() ;
      delay(10) ;
      READ_TEA5767() ;  // RSSI
      break ;
    case 5: 
      VOLUME = VOLUME - 1 ;
      if(VOLUME < VOLMIN ) VOLUME = VOLMIN ;
      SET_VOLUME() ;
      break ;
  }
  rotation = false ;
  UpdateOLED() ; 
  }

  
  // //////////////////////////////////////////////////
  // WAS IT ROTATED LEFT >>> DECREASE
  // //////////////////////////////////////////////////
  if(!clockwise)
  {
  // Serial.println("CCW") ; 
  switch(CURSOR)
  {
    case 2: 
      freq = freq + 1.0 ; 
      if(freq > BandStop) freq = BandStop ;
      HiLoOptimiser() ;
      delay(10) ;
      READ_TEA5767() ;  // RSSI
      break ;
    case 3: 
      freq = freq + 0.1 ; 
      if(freq > BandStop) freq = BandStop ;
      HiLoOptimiser() ;
      delay(10) ;
      READ_TEA5767() ;  // RSSI
      break ;
    case 4: 
      freq = freq + 0.01 ;
      if(freq > BandStop) freq = BandStop ; 
      HiLoOptimiser() ;
      delay(10) ;
      READ_TEA5767() ;  // RSSI
      break ;
    case 5: 
      VOLUME = VOLUME + 1 ;
      if(VOLUME > VOLMAX ) VOLUME = VOLMAX ;
      SET_VOLUME() ;
      break ;
  }
  rotation = false ;
  UpdateOLED() ; 
  }
}


void READ_TEA5767()
{  
  pinMode(RX_DAT_PIN, INPUT);
  digitalWrite(RX_CLK_PIN, HIGH);
  delay(1) ;
  digitalWrite(WriteRead, HIGH); 
  delay(1) ;
  digitalWrite(WriteRead, LOW); 
  delay(1) ;
  RAM[0] = shiftIn(RX_DAT_PIN, RX_CLK_PIN, MSBFIRST) ;
  RAM[1] = shiftIn(RX_DAT_PIN, RX_CLK_PIN, MSBFIRST) ;
  RAM[2] = shiftIn(RX_DAT_PIN, RX_CLK_PIN, MSBFIRST) ;
  RAM[3] = shiftIn(RX_DAT_PIN, RX_CLK_PIN, MSBFIRST) ;
  RAM[4] = shiftIn(RX_DAT_PIN, RX_CLK_PIN, MSBFIRST) ;
  Stereo = (RAM[2] & 0x80) >> 7 ;
  RSSI = (RAM[3] & 0xF0) >> 4 ;
  RF = (RAM[0] & 0x80) >> 7 ;
  BLF = (RAM[0] & 0x40) >> 6 ;
  IFCounts = RAM[2] & 0x7F ;
}


void WRITE_TEA5767()
{
  pinMode(RX_DAT_PIN, OUTPUT);
  digitalWrite(RX_CLK_PIN, LOW); delay(1) ;
  digitalWrite(WriteRead, LOW); delay(1) ;
  digitalWrite(WriteRead, HIGH); delay(1) ;
  if(HLSI == 1) pll=(int)(((freq+0.225)*122.0703125)+0.5);
  if(HLSI == 0) pll=(int)(((freq-0.225)*122.0703125)+0.5);
  RAM[5] = HIBYTE(pll) | (MUTE<<7) | (SM<<6) ; 
  RAM[6] = LOBYTE(pll) ; 
  RAM[7] = (SUD<<7)|(SSL<<5)|(HLSI<<4)|(MS<<3)|(MR<<2)|(ML<<1) ; 
  RAM[8] = (BL<<5)|(XTAL<<4)|(SMUTE<<3)|(HCC<<2)|(SNC<<1);
  RAM[9] = DTC<<6 ;  
  shiftOut(RX_DAT_PIN, RX_CLK_PIN, MSBFIRST, RAM[5]);
  shiftOut(RX_DAT_PIN, RX_CLK_PIN, MSBFIRST, RAM[6]);
  shiftOut(RX_DAT_PIN, RX_CLK_PIN, MSBFIRST, RAM[7]);
  shiftOut(RX_DAT_PIN, RX_CLK_PIN, MSBFIRST, RAM[8]);
  shiftOut(RX_DAT_PIN, RX_CLK_PIN, MSBFIRST, RAM[9]);
}


void HiLoOptimiser()
{
  int RSSIHigh = 0 ;
  int RSSILow = 0 ;
  float Frequency = freq ;
  SM = 0 ;    // NOT IN SEARCH MODE
  VolumeMute() ;
  if (Frequency > BandStop) Frequency = BandStop ;
  if (Frequency < BandStart) Frequency = BandStart ;
  // //////////////////////////////////////////////////
  // RSSIHigh is at freq + 450 kHz
  // //////////////////////////////////////////////////
  freq = Frequency + 0.225 ;
  HLSI = 1 ;
  WRITE_TEA5767() ; 
  delay(10) ;
  READ_TEA5767() ;
  RSSIHigh = RSSI ;
  // //////////////////////////////////////////////////
  // RSSILow is at freq - 450 kHz
  // //////////////////////////////////////////////////
  HLSI = 0 ;
  freq = Frequency - 0.225 ;
  WRITE_TEA5767() ; 
  delay(10) ;
  READ_TEA5767() ;
  RSSILow = RSSI ;
  // //////////////////////////////////////////////////
  // EVALUATION SEE APPLICATION NOTE PAGE 27
  // //////////////////////////////////////////////////
  if(RSSIHigh < RSSILow)
  {
    // OPTIMUM SETTING IS HIGH SIDE INJECTION
    HLSI = 1 ;
    freq = Frequency ;
    WRITE_TEA5767() ; 
  }
  else
  {
    // OPTIMUM SETTING IS LOW SIDE INJECTION
    HLSI = 0 ; 
    freq = Frequency ;
    WRITE_TEA5767() ;    
  }
  delay(27);
  READ_TEA5767() ;
  VolumeUnMute() ;
  UpdateOLED() ;
}


void SCAN()
{
  freq = BandStart ;
  while(freq <= BandStop)
  {
    HiLoOptimiser() ;
    if(RSSI >=4)
    {
    if(freq <100.0) Serial.print(" ");
    Serial.print(freq,3); Serial.print(" RSSI: ");
    Serial.print(RSSI,DEC);
    Serial.print(" IFC: ");
    Serial.println(IFCounts,DEC);
    }
    freq += 0.098304 ;
    delay(30);
  } 
}

void SearchUP()
{
  Serial.println("SEARCHING ...");
  SearchMode = true ;
  UpdateOLED() ;
  int RSSILAST = 0 ;
  int RSSICURR = 0 ;
  int RSSINEXT = 0 ;
  boolean STOPSEARCH = false ;
  float Frequency = freq ;
  while(!STOPSEARCH)
  {
    freq += 0.098304 ;
    HiLoOptimiser() ;
    if(RSSI >=4)
    {
    if(freq <100.0) Serial.print(" ");
    Serial.print(freq,3); 
    Serial.print(" RSSI: ");
    if(RSSI < 10) Serial.print(" ");
    Serial.print(RSSI,DEC);
    Serial.print(" IFC: ");
    Serial.println(IFCounts,DEC);
    if((IFCounts > 56) && (IFCounts < 71))
      {
        STOPSEARCH = true ;
        SearchMode = false ;
        Serial.println("FOUND.");
      }
    } // END RSSI-IF
    if(freq >= BandStop)
    {
      freq = BandStart ;
      STOPSEARCH = true ;
      SearchMode = false ;
    } // END BANDSTOP
    delay(100);
    } // END WHILE 
  SearchMode = false ;
  UpdateOLED() ;
}


// ///////////////////////////////////////////////////////////// 
// UNUSED FUNCTIONS
// ///////////////////////////////////////////////////////////// 

void FREQ_TEA5767(float FRQ)
{
  int aux ;
  if (FRQ > BandStop) FRQ = BandStop ;
  if (FRQ < BandStart) FRQ = BandStart ;
  pll = (int)((( FRQ + 0.225 ) * 122.0703125 ) + 0.5 );
  RAM[5] = HIBYTE(pll) ;
  RAM[6] = LOBYTE(pll) ;
  // Search Up, Low Volume, High Side Injection, Stereo, No Mute
  RAM[7] = 0xC0; 
  // EU Band, Clock 32768, Stero Noise Cancelling On
  RAM[8] = 0x12 ; 
  RAM[9] = 0x00 ; // De-Emphasis Time Constant is 50 µs
  pinMode(RX_DAT_PIN, OUTPUT);
  delay(1) ;
  digitalWrite(WriteRead, LOW); 
  delay(1) ;
  digitalWrite(WriteRead, HIGH); 
  delay(1) ;
  shiftOut(RX_DAT_PIN, RX_CLK_PIN, MSBFIRST, RAM[5]);
  shiftOut(RX_DAT_PIN, RX_CLK_PIN, MSBFIRST, RAM[6]);
  shiftOut(RX_DAT_PIN, RX_CLK_PIN, MSBFIRST, RAM[7]);
  shiftOut(RX_DAT_PIN, RX_CLK_PIN, MSBFIRST, RAM[8]);  
  shiftOut(RX_DAT_PIN, RX_CLK_PIN, MSBFIRST, RAM[9]);
}


// ///////////////////////////////////////////////////////////// 

void loop() 
{
  if (action)
  {
    if(pressed) ButtonPressed() ;
    if(rotation) ButtonRotated() ;
    action = false ;
    UpdateOLED() ;
  }
  delay(9) ;
}

// ///////////////////////////////////////////////////////////// 
// END OF FILE
// ///////////////////////////////////////////////////////////// 

✈ Use as a Spectrum Analyser

Radio Spectrum Hua Hin, 18.10.2019, telescopic antenna, inside my room

A tuneable receiver mayst also be used as a spectrum analyser. The trick is, that you change the frequency of the receiver sequentially over the full band and record the RSSI values. To test this functionality, the function "SCAN()" has been written. The values then can be evaluated with the spreadsheet program of your choice. Here, the vertical resolution is 3 dB. (Given by TEA5767 module).

The highest signal level at 91.25 MHz is from KCS Radio (สถานีวิทยุกระจายเสียงทหารอากาศ), another dominant station is at 98.75 MHz (สถานีวิทยุกระจายเสียงแห่งประเทศไทย) or at 102.5 MHz (Hua Hin Surf FM, หัวหิน เชิรฟ เอฟ. เอ็ม).

Information is from : www.asiawaves.net.

✈ Some more Impressions ...

✈ Khwankeo Vajarodaya

H.E. Mr. Khwankeo Vajarodaya was born on September 3rd in 1928. He grew up an studied - inter alia - at the École hôtelière in Lausanne. He soon then become a member of "Le Club des Chefs des Chefs". In this function he was Lecturer as well as Reference in all questions of Thai Cuisine. He also wrote the Book "The Evolution and Art of Setting Tables, Catering, Beverages and Menus" (1999).

He was also the President of the Royal Distant Learning Television Project of H.M. King Bhumibol Adulyadej. (Who's goal was to ensure that every Thai child in the Kingdom should have an opportunity to learn.) Nowadays (2019), more than 14 channels broadcast lectures from the Royal Wang Klai Kang Won School in Hua Hin via Satellite to rural areas in Thailand as well as in neighboring countries. Parallel to that, the lectures are available via internet. Whenever you want.

He used the Callsign "Wachara 1", in thai "วัชระ ๑".

He passed away on January 28th, 2017.

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