#include <Servo.h>
Servo myservo;

int LDR = 0; // light sensor connected to A0
int prevValue = 0; // reference point
int curValue = 0; // to check against prevValue
void setup() {
  myservo.attach(13);
  pinMode(LDR, INPUT); //put light sensor as input
  myservo.write(140); // put servo in starting position
  Serial.begin(9600); // speed to interact with Arduino
  curValue = analogRead(LDR); //initialize curValue
}

void loop() {
  prevValue = curValue; // put prevValue to reference point
  curValue = analogRead(LDR); // get new value for light sensor
  Serial.println(curValue); //print sensor data (0-1023)
  if(curValue - prevValue >= 20) { // if light spikes up
    myservo.write(180); //move servo to button
    delay(400); //hold servo in current position
    myservo.write(140); //move servo back to initial position
  }
  delay(100); // wait a tenth of a second for new data
}