code.cpp

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

// Hardware Pin Definitions
#define LED PA6           
#define SPEED_SENSOR PA0  
#define I2C_ADDR    0x27
#define LCD_COLUMNS 20
#define LCD_LINES   4

// Timing and State Variables
unsigned long previousMillis = 0;
unsigned long lcdUpdateMillis = 0;
int blinkInterval = 500; 
bool ledState = false;

// Initialize LCD
LiquidCrystal_I2C lcd(I2C_ADDR, LCD_COLUMNS, LCD_LINES);

void setup() {
  pinMode(LED, OUTPUT);
  digitalWrite(LED, LOW);
  
  // Initialize LCD
  lcd.init();
  lcd.backlight();
  lcd.setCursor(0, 0);
  lcd.print("AUTOMOTIVE SYS V1.0");
}

void loop() {
  unsigned long currentMillis = millis();

  // 1. READ & MAP SPEED DATA
  int potValue = analogRead(SPEED_SENSOR);
  // Map 0-1023 to automotive blink range: 1000ms (60 BPM) to 250ms (240 BPM/Hyperflash)
  blinkInterval = map(potValue, 0, 1023, 1000, 250);
  
  // Calculate simulated speed (0-150 km/h) and BPM for the display
  int simulatedSpeed = map(potValue, 0, 1023, 0, 150);
  int currentBPM = 60000 / (blinkInterval * 2); // Standard BPM calculation

  // 2. NON-BLOCKING BLINK LOGIC
  if (currentMillis - previousMillis >= blinkInterval) {
    previousMillis = currentMillis;
    ledState = !ledState;
    digitalWrite(LED, ledState ? HIGH : LOW);
  }

  // 3. REFRESH LCD (Every 200ms to avoid flickering)
  if (currentMillis - lcdUpdateMillis >= 200) {
    lcdUpdateMillis = currentMillis;
    
    lcd.setCursor(0, 1);
    lcd.print("Speed: ");
    lcd.print(simulatedSpeed);
    lcd.print(" km/h    "); // Spaces clear leftover digits

    lcd.setCursor(0, 2);
    lcd.print("Rate:  ");
    lcd.print(currentBPM);
    lcd.print(" BPM     ");

    // Visual Dashboard Indicator
    lcd.setCursor(0, 3);
    if (ledState) {
      lcd.print("<<< SIGNAL ON  >>>");
    } else {
      lcd.print("    SIGNAL OFF    ");
    }
  }
}