//Automatic Car Lights- from ChatGPT
//modified by Pat McMahon- 26/4/2026
//I asked ChatGPT-"Using the Arduino IDE and a Uno, code a sketch to turn on an led when an attached LDR is covered up, off when open to light".
// I then modified the code for 3 LEDS, Blue,Orange and Red.
const int ldrPin = A0;   // LDR connected to analog pin A0
const int BlueledPin = 9;    // LED connected to digital pin 9
const int OrangeledPin = 10;    // LED connected to digital pin 10
const int RedledPin = 11;    // LED connected to digital pin 11

int lightValue = 0;
int threshold = 400;     // Adjust this after testing

void setup() {
  pinMode(BlueledPin, OUTPUT);
  pinMode(OrangeledPin, OUTPUT);
  pinMode(RedledPin, OUTPUT);
  Serial.begin(9600);    // For debugging
}

void loop() {
  lightValue = analogRead(ldrPin);

  Serial.println(lightValue); // See values in Serial Monitor

  if (lightValue < threshold) {
    // DARK → LED ON
    digitalWrite(BlueledPin, HIGH);
    digitalWrite(OrangeledPin, HIGH);
    digitalWrite(RedledPin, HIGH);
  } else {
    // LIGHT → LED OFF
    digitalWrite(BlueledPin, LOW);
    digitalWrite(OrangeledPin, LOW);
    digitalWrite(RedledPin, LOW);
  }

  delay(200);
}