Objective:A smart street light system that automatically turns the led on when it gets dark.

• Materials:
• Breadboard (generic)
• Resistor 10k ohm
• LDR, 5 Mohm
• Jumper wires (generic)
• LED, White
• Arduino UNO

Code: also attached to the post 

*/

const   int ledpin = 13; // ledpin and lightpin are not changed throughout the process

const   int lightpin = A2;

const int LIGHT = 10; // sets LIGHT value for light sensor

void   setup() {

  Serial.begin(9600);

  pinMode(ledpin, OUTPUT);

  pinMode(lightpin,   INPUT);

}

void loop() {

  int lightsens = analogRead(lightpin); // reads   analog data from light sensor

  if (lightsens < LIGHT) {

    digitalWrite(ledpin,   HIGH); //turns led on

    delay(1500);

  }

  else {

    digitalWrite(ledpin,   LOW);

  }

}