solar_tracker.ino

#include <Servo.h>

const int LDR_LEFT_PIN = 2;
const int LDR_RIGHT_PIN = 3;
const int SERVO_PIN = 9;

Servo tracker;

int angle = 90;

const int CENTER_ANGLE = 90;
const int STEP = 5;
const int MIN_ANGLE = 30;
const int MAX_ANGLE = 150;

const int LOOP_DELAY = 80;

void setup() {
  pinMode(LDR_LEFT_PIN, INPUT);
  pinMode(LDR_RIGHT_PIN, INPUT);

  tracker.attach(SERVO_PIN);
  tracker.write(angle);

  Serial.begin(9600);
}

void loop() {
  int left = digitalRead(LDR_LEFT_PIN);
  int right = digitalRead(LDR_RIGHT_PIN);

  left = (left  == 0) ? 1 : 0;
  right = (right == 0) ? 1 : 0;

  if (left == 1 && right == 0) {
    angle -= STEP;
  }
  else if (right == 1 && left == 0) {
    angle += STEP;
  }
  else if (left == 1 && right == 1) {
    if (angle < CENTER_ANGLE) angle += STEP;
    else if (angle > CENTER_ANGLE) angle -= STEP;
  }

  angle = constrain(angle, MIN_ANGLE, MAX_ANGLE);

  tracker.write(angle);

  Serial.print(left);
  Serial.print(",");
  Serial.print(right);
  Serial.print(",");
  Serial.println(angle);

  delay(LOOP_DELAY);
}