// Single Axis Solar Tracker using L298N & LDR Modules

const int LDR_North = A1;  // LDR facing North
const int LDR_South = A2;  // LDR facing South

const int forward = 9;     // L298N Forward pin (piston extends)
const int backward = 8;    // L298N Backward pin (piston retracts)
const int speedpin = 10;    // PWM Speed control for piston

const int threshold = 50;  // Light difference threshold for movement
const int sunsetThreshold = 20; // Light level below which tracker resets

void setup() {
  Serial.begin(9600);

  pinMode(forward, OUTPUT);
  pinMode(backward, OUTPUT);
  pinMode(speedpin, OUTPUT);
}

void loop() {
  int lightNorth = analogRead(LDR_North);
  int lightSouth = analogRead(LDR_South);

  Serial.print("LDR North: ");
  Serial.println(lightNorth);
  Serial.print("LDR South: ");
  Serial.println(lightSouth);

  int luxDiff = lightNorth - lightSouth;
  int speed = map(abs(luxDiff), 0, 500, 0, 200);
  speed = constrain(speed, 100, 200); // Slow movement speed

  // Move tracker based on light difference
  if (luxDiff > threshold) {
    digitalWrite(forward, HIGH);
    digitalWrite(backward, LOW);
    analogWrite(speedpin, speed);
  } 
  else if (luxDiff < -threshold) {
    digitalWrite(forward, LOW);
    digitalWrite(backward, HIGH);
    analogWrite(speedpin, speed);
  } 
  else {
    digitalWrite(forward, LOW);
    digitalWrite(backward, LOW);
    analogWrite(speedpin, 0);
  }

  // Cloud detection (pause if sudden drop in sunlight)
  static int previousLux = (lightNorth + lightSouth) / 2;
  int currentLux = (lightNorth + lightSouth) / 2;

  if (previousLux - currentLux > 100) { // Sudden large drop in sunlight
    Serial.println("Cloud detected! Pausing movement...");
    digitalWrite(forward, LOW);
    digitalWrite(backward, LOW);
    analogWrite(speedpin, 0);
    delay(30000); // Pause for 30 seconds
  }
  previousLux = currentLux;

  // Return to start position at sunset
  if (lightNorth < sunsetThreshold && lightSouth < sunsetThreshold) {
    Serial.println("Sunset detected! Returning to start position...");
    digitalWrite(forward, LOW);
    digitalWrite(backward, HIGH);
    analogWrite(speedpin, 150);
    delay(5000); // Move for 5 seconds
    digitalWrite(backward, LOW);
  }

  delay(5000); // Delay for 5 seconds to slow down movements
}