Arduino Netgun

main.ino

#include <Servo.h>

#define PIN_PHOTO_SENSOR A0
#define PIN_SERVO 11

#define LIGHT_LIMIT_K 80

#define MAX_POSITIVE_SPEED 180
#define MAX_NEGATIVE_SPEED 0
#define REST_SPEED 90

Servo servo;

bool isRotated = false;

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

  servo.attach(PIN_SERVO);
  servo.write(REST_SPEED);
}

void loop() {  
  int val = analogRead(PIN_PHOTO_SENSOR);
  bool nextIsRotated = val < LIGHT_LIMIT_K;
  Serial.println(val);

  if (nextIsRotated != isRotated) {
    isRotated = nextIsRotated;

    servo.write(
      isRotated
        ? MAX_POSITIVE_SPEED
        : MAX_NEGATIVE_SPEED
    );

    delay(250);

    servo.write(REST_SPEED);
    
    delay(1000);
  }
}