how to use ldr in Arduino

How to use LDR with relay module in Arduino :

Full video link with description:

                

Full video link

Code :

void setup() {

  pinMode(4,INPUT);

  pinMode(3,OUTPUT);

  digitalWrite(4,HIGH);

  

  // put your setup code here, to run once:

}

void loop() {

   

   if (digitalRead(4) == HIGH){

    digitalWrite(3,LOW);

   }

                     

   else{

    digitalWrite(3,HIGH);

   

  }}

  // put your main code here, to run repeatedly:

How to make Robot Dog

Wanted Things:

    1.Arduino

    2.carboard

    3.Servo motors

    4.Jumper Wire

    5.Battery

Video Link: YouTube (Robot Dog)

circuit Diagram:

Code:

#include<Servo.h>

Servo rs;

Servo ls;

int i = 1;

void setup() {

  rs.attach(9);

  ls.attach(8);

  pinMode(7, INPUT);

  // put your setup code here, to run once:

}

void loop() {

  rs.write(90);

  ls.write(110);

  delay(3000);

    //Servo walk

  while(digitalRead(7) == HIGH){

    rs.write(128);

    delay(200);

    rs.write(96);

    delay(100);

    ls.write(65);

    delay(100);

    ls.write(100);

    delay(100);

  }

}