#include <Servo.h>     // Library for Servo Motor

          int potpin=A0;// initialize analog pin 0, connected with photovaristor

          int ledpin=13;// initialize digital pin 13, output regulating the brightness of LED

          int val=0;// initialize variable val

          Servo myServo;   // define servo name



          /* The setup() function is called when a sketch starts. It is used to initialize variables, pin modes, start using libraries, etc. This function will only run once, after each power up or reset of the Arduino board. */



          void setup()

          {

          pinMode(ledpin,OUTPUT);// set digital pin 13 as “output”

          Serial.begin(9600);   // set baud rate at “9600”

          myServo.attach(5);   // servo pin

          myServo.write(0);     // servo start position

          }



          /* The loop() function executes the program repeatedly until Specified. */



          void loop()

          {

          val=analogRead(potpin);// read the analog value of the sensor and assign it to val

          Serial.println(val);// display the value of val

          analogWrite(ledpin,val);// turn on the LED and set up brightness（maximum output value 255）

          delay(10);// wait for 0.01

          if(val>250)

          {

          myServo.write(90);

          }

          else

          {

          myServo.write(0);

          }

          }

val=analogRead(potpin);// read the analog value of the sensor and assign it to val

Serial.println(val);// display the value of val

analogWrite(ledpin,val);// turn on the LED and set up brightness（maximum output value 255）

delay(10);// wait for 0.01

if(val>250)

{

   myServo.write(90); 

}

if(val<260)

{

   myServo.write(0);

}

}