DIY Retro Look FM Radio with Linear Scale

/// SI4703 Nano Rotary Neostrip sketch mit der SI4703_Breakout library von Simon Monk. Auf die aktuellere Version achten! Diese
/// hat bei der Objektdefinition 4 Parameter, die alte Version nur 3.
/// Jupp Haffner 15.9.2017
///
/// Wiring
/// ------
/// The SI4703 board has to be connected by using the following connections:
/// | Arduino UNO pin    | Radio chip signal  |
/// | -------------------| -------------------|
/// | 3.3V (red)         | VCC                |
/// | GND (black)        | GND                |
/// | A5 or SCL (yellow) | SCLK               |
/// | A4 or SDA (blue)   | SDIO               |
/// | D2 (white)         | RST                |

#include <Arduino.h>
#include <Wire.h>
#include <radio.h>
#include <Si4703_Breakout.h>

/*SI4703 - Pins*/
int resetPin = 2;
int SDIO = A4;
int SCLK = A5;
int RDSInterruptPin = 3; // GPIO2 for RDS Interrupt

int StereoLED = 11;
int AF_LED    = 12;

int volume = 28;
int rssi; //signal-level
int tune; //AFC
int stereo;

/*Init SI4703 Driver*/
Si4703_Breakout radio(resetPin, SDIO, SCLK, RDSInterruptPin);

//Rotary Encoder http://henrysbench.capnfatz.com/henrys-bench/arduino-sensors-and-input/keyes-ky-040-arduino-rotary-encoder-user-manual/
int clk = 3;  // Connected to CLK on KY-040
int dt = 7;  // Connected to DT on KY-040
volatile int channel = 1017;
volatile byte INTFLAG1 = 0; // interrupt status flag
volatile byte UP_FLAG = 0; //seekUp
volatile byte DOWN_FLAG = 0; //seekDn

#include <Adafruit_NeoPixel.h>
#define Din 4
int anz_led = 21; // Anzahl der LED's
Adafruit_NeoPixel strip = Adafruit_NeoPixel(anz_led, Din, NEO_GRB + NEO_KHZ800);
// Parameter 1 = number of pixels in strip
// Parameter 2 = pin number (most are valid)
// Parameter 3 = pixel type flags, add together as needed:
//   NEO_KHZ800  800 KHz bitstream (most NeoPixel products w/WS2812 LEDs)
//   NEO_KHZ400  400 KHz (classic 'v1' (not v2) FLORA pixels, WS2811 drivers)
//   NEO_GRB     Pixels are wired for GRB bitstream (most NeoPixel products)
//   NEO_RGB     Pixels are wired for RGB bitstream (v1 FLORA pixels, not v2)
int wc = 0; //wheel-color 0 = grun, 80 = rot, 160 = blau
int led = 0;
int led_pos = channel;

void setup()
{

  //Rotary Encoder KY-040 pull up's built in
  pinMode (clk, INPUT);
  pinMode (dt, INPUT);
  // interrupt 1 digital pin 3 positive edge trigger
  attachInterrupt(digitalPinToInterrupt(clk), flag, RISING);
     
  //Initialize and Power up the SI4703
  radio.powerOn();
  radio.powerOn();
  radio.setVolume(volume);
  radio.setChannel(channel);

  //Print Informations to Serial Monitor
  Serial.begin(9600);
  displayInfo();

  strip.begin();
  strip.setBrightness(64); //range 0 (off) to 255 (max brightness)
  strip.show(); // Initialize all pixels to 'off'
  UpdateLed();

}

void loop()
{

//Rotary Encoder
  if (INTFLAG1)   {
       Serial.println("ISP ausgelost");
       if (UP_FLAG) SI4703_seekUpAuto();
       if (DOWN_FLAG) SI4703_seekDnAuto();
       // clear flags
       INTFLAG1 = 0;
       UP_FLAG = 0;
       DOWN_FLAG = 0;
       delay(40);
  }
}

//ISR for Encoder: http://www.bristolwatch.com/arduino/arduino2.htm
void flag() {
  INTFLAG1 = 1;
  // CW
  if (digitalRead(clk) && digitalRead(dt)) {
    UP_FLAG = 1;
  }
  // CCW
  if (digitalRead(clk) && !digitalRead(dt)) {
    DOWN_FLAG = 1;
  }
}

uint32_t Wheel(byte WheelPos) {
  if (WheelPos < 85) {
    return strip.Color(WheelPos * 3, 255 - WheelPos * 3, 0);
  } else if (WheelPos < 170) {
    WheelPos -= 85;
    return strip.Color(255 - WheelPos * 3, 0, WheelPos * 3);
  } else {
    WheelPos -= 170;
    return strip.Color(0, WheelPos * 3, 255 - WheelPos * 3);
  }
}

void displayInfo (void)
   {
   rssi=radio.getRSSI();
   tune=radio.getTune();
   stereo=radio.getStereo();
   Serial.print("\n\nChannel: "); Serial.print(channel/10.);Serial.println(" MHz");
   Serial.print("Volume: "); Serial.println(volume);
   Serial.print("RSSI: ");Serial.print(rssi);Serial.println("dB");
   Serial.print("Tune: ");
   if(tune==0)Serial.println("AFC Tuned!!");
   if(tune==1)Serial.println("AFC Tuning...");
   Serial.print("Stereo: ");
   if(stereo==1){Serial.println("true");digitalWrite(StereoLED, HIGH);}
   if(stereo==0){Serial.println("false");digitalWrite(StereoLED, LOW);}
   }

void SI4703_seekUpAuto (void)
{
      channel+=1;
      radio.setVolume(0);
      radio.setChannel(channel);
      delay(100);
      for(int seekup=channel;; seekup++)
      {
         if(seekup>1080)seekup=875;
         Serial.print(seekup/10.);Serial.println(" MHz");
         radio.setChannel(seekup);
         led_pos = seekup;
         UpdateLed();
         delay(30);
         int SI4703AFC_Tune=radio.getTune();
         int SI4703RSSI_Tune=radio.getRSSI();
         delay((SI4703RSSI_Tune*3));
         if(((SI4703AFC_Tune==false)&&(SI4703RSSI_Tune>25)))
         {
            radio.setVolume(volume);
            channel=seekup;
            displayInfo();
            break;
         }
      }   
}

void SI4703_seekDnAuto (void)
{
      channel-=1;
      radio.setVolume(0);
      radio.setChannel(channel);
      delay(100);
      for(int seekdown=channel;; seekdown--)
      {        
         if(seekdown<=875)seekdown=1080;
         Serial.print(seekdown/10.);Serial.println(" MHz");
         radio.setChannel(seekdown);
         led_pos = seekdown;
         UpdateLed();
         delay(30);
         int SI4703AFC_Tune=radio.getTune();
         int SI4703RSSI_Tune=radio.getRSSI();
         delay((SI4703RSSI_Tune*3));
         if(((SI4703AFC_Tune==false)&&(SI4703RSSI_Tune>25)))
         {
            radio.setVolume(volume);
            channel=seekdown;
            displayInfo();
            break;
         }
      }
}

void UpdateLed()
{
rssi=radio.getRSSI();
tune=radio.getTune();
stereo=radio.getStereo();
strip.setPixelColor(led, strip.Color( 0, 0, 0));
led = map(led_pos, 870, 1080, 0, (anz_led - 1));
wc = 0; //grun
if (rssi >= 25) wc = 80; //rot
if (tune) wc = 160; //blau
strip.setPixelColor(led, Wheel(wc));
strip.show();
delay(20);
}