// Pin definitions
int mosfetPin = 6;        // MOSFET Gate control pin
int ledRed = 9;           // Red LED (low voltage indicator)
int ledYellow = 10;       // Yellow LED (medium voltage indicator)
int ledGreen = 11;        // Green LED (high voltage indicator)
int ledBlue = 12;         // Blue LED (load indication)

int analogPin = A0;       // Analog pin to read battery voltage
int batteryVoltage = 0;   // Variable to store battery voltage
float voltageReading = 0; // Variable to store converted voltage

// Voltage thresholds for the LEDs (adjusted for 1.5V AA battery)
float lowVoltage = 1.0;   // Low battery threshold in Volts
float mediumVoltage = 1.2; // Medium battery threshold in Volts
float highVoltage = 1.3;  // High battery threshold in Volts

void setup() {
  // Set pin modes
  pinMode(mosfetPin, OUTPUT);  // Set MOSFET control pin as output
  pinMode(ledRed, OUTPUT);      // Set Red LED as output
  pinMode(ledYellow, OUTPUT);   // Set Yellow LED as output
  pinMode(ledGreen, OUTPUT);    // Set Green LED as output
  pinMode(ledBlue, OUTPUT);     // Set Blue LED as output

  Serial.begin(9600);          // Initialize serial monitor for debugging
}

void loop() {
  // Read the battery voltage from the analog pin
  int sensorValue = analogRead(analogPin);  
  voltageReading = sensorValue * (5.0 / 1023.0);  // Convert to voltage (Arduino uses 5V reference)
  
  // Print the battery voltage to the serial monitor for debugging
  Serial.print("Battery Voltage: ");
  Serial.println(voltageReading);

  // Control LEDs based on battery voltage
  if (voltageReading < lowVoltage) {
    // Low voltage condition, turn off MOSFET, indicate with Red LED
    digitalWrite(mosfetPin, LOW);    // MOSFET OFF (no load)
    digitalWrite(ledBlue, LOW);      // Turn off Blue LED (no load)
    turnOffLEDs();
    digitalWrite(ledRed, HIGH);      // Turn on Red LED (low voltage)
  } 
  else if (voltageReading >= lowVoltage && voltageReading < mediumVoltage) {
    // Medium voltage condition, turn on MOSFET, indicate with Yellow LED
    digitalWrite(mosfetPin, HIGH);  // MOSFET ON (apply load)
    digitalWrite(ledBlue, HIGH);    // Turn on Blue LED (load condition)
    turnOffLEDs();
    digitalWrite(ledYellow, HIGH);  // Turn on Yellow LED (medium voltage)
  } 
  else if (voltageReading >= mediumVoltage && voltageReading < highVoltage) {
    // High voltage condition, turn on MOSFET, indicate with Green LED
    digitalWrite(mosfetPin, HIGH);  // MOSFET ON (apply load)
    digitalWrite(ledBlue, HIGH);    // Turn on Blue LED (load condition)
    turnOffLEDs();
    digitalWrite(ledYellow, HIGH);  // Turn on Yellow LED (medium voltage)
  } 
  else {
    // Full charge condition, turn off MOSFET, indicate with Green LED
    digitalWrite(mosfetPin, LOW);   // MOSFET OFF (no load)
    digitalWrite(ledBlue, LOW);     // Turn off Blue LED (no load)
    turnOffLEDs();
    digitalWrite(ledGreen, HIGH);   // Turn on Green LED (high voltage)
  }

  // Small delay before the next reading
  delay(500); 
}

// Function to turn off all LEDs
void turnOffLEDs() {
  digitalWrite(ledRed, LOW);
  digitalWrite(ledYellow, LOW);
  digitalWrite(ledGreen, LOW);
}