Arduino code

#include <Wire.h>
#include <RDA5807.h>
#include <LiquidCrystal_I2C.h>

RDA5807 radio;

// --- LCD Configuration ---
LiquidCrystal_I2C lcd(0x27, 16, 2); // Try 0x27 or 0x3F depending on your module

// --- Button configuration ---
const int buttonPin = 2;   // Push button connected to digital pin 2
int lastButtonState = HIGH;
int currentButtonState;
unsigned long lastDebounceTime = 0;
unsigned long debounceDelay = 200; // debounce time in ms

// --- Frequency list (in 100 kHz units) ---
uint16_t frequencies[] = {9350, 9830, 10640, 10140, 9970, 10650};
int freqCount = sizeof(frequencies) / sizeof(frequencies[0]);
int currentFreqIndex = 0;

void setup() {
  Serial.begin(115200);
  Serial.println("Initializing RDA5807M FM Receiver...");

  pinMode(buttonPin, INPUT_PULLUP); // use internal pull-up resistor

  // Initialize LCD
  lcd.init();
  lcd.backlight();
  lcd.clear();
  lcd.setCursor(0, 0);
  lcd.print("FM Receiver");
  delay(1000);

  // Initialize radio
  radio.setup();
  radio.setVolume(10); // Volume range: 0–15
  delay(100);

  // Tune to the first frequency
  radio.setFrequency(frequencies[currentFreqIndex]);
  showFrequency();
  Serial.print("Tuned to ");
  Serial.print(frequencies[currentFreqIndex] / 100.0);
  Serial.println(" MHz");
}

void loop() {
  currentButtonState = digitalRead(buttonPin);

  // Detect button press (active LOW)
  if (currentButtonState == LOW && lastButtonState == HIGH && (millis() - lastDebounceTime) > debounceDelay) {
    lastDebounceTime = millis();

    // Change to next frequency
    currentFreqIndex++;
    if (currentFreqIndex >= freqCount) {
      currentFreqIndex = 0; // Wrap around
    }

    // Tune radio
    radio.setFrequency(frequencies[currentFreqIndex]);
    showFrequency();

    Serial.print("Changed to: ");
    Serial.print(frequencies[currentFreqIndex] / 100.0);
    Serial.println(" MHz");
  }

  lastButtonState = currentButtonState;
  delay(100);
}

// --- Function to display frequency on LCD ---
void showFrequency() {
  lcd.clear();
  lcd.setCursor(0, 0);
  lcd.print("FM Receiver");
  lcd.setCursor(0, 1);
  lcd.print("Freq: ");
  lcd.print(frequencies[currentFreqIndex] / 100.0);
  lcd.print(" MHz");
}