void setup() {  
  pinMode(28, INPUT); 
  pinMode(5, OUTPUT); 
  Serial1.begin(115200);
  Serial1.println("Raspberry Pi Pico LDR Project");
}

void loop() {
  int ldr=digitalRead(28);
  Serial1.println(ldr);
  if(ldr>0){
    digitalWrite(5,HIGH);
  }else{
    digitalWrite(5,LOW);
  }
  delay(1000);
}
BOOTSELLED1239USBRaspberryPiPico©2020RP2-8020/21P64M15.00TTT
NOCOMNCVCCGNDINLED1PWRRelay Module