int LED_1 = 2;  
int LED_2 = 3;
int LED_3 = 4;
int LED_4 = 5;
int valor;  
void setup() {
Serial.begin(9600);  
Serial.println("Valores del potenciómetro");  

pinMode(LED_1, OUTPUT);  
pinMode(LED_2, OUTPUT);
pinMode(LED_3, OUTPUT);
pinMode(LED_4, OUTPUT);
}

void loop() {
valor = analogRead(A0); 

Serial.print("El valor es: ");  
Serial.println(valor);

delay(1000);

 if (valor >= 0 && valor <= 256) {  
digitalWrite(LED_1, HIGH);
digitalWrite(LED_2, LOW);
digitalWrite(LED_3, LOW);
 digitalWrite(LED_4, LOW);
 }
 else if (valor >= 257 && valor <= 511) {  
digitalWrite(LED_1, HIGH);
digitalWrite(LED_2, HIGH);
digitalWrite(LED_3, LOW);
digitalWrite(LED_4, LOW);
}
else if (valor >= 512 && valor <= 767) {  
digitalWrite(LED_1, HIGH);
digitalWrite(LED_2, HIGH);
digitalWrite(LED_3, HIGH);
digitalWrite(LED_4, LOW);
}
else if (valor >= 768 && valor <= 1023) {  
digitalWrite(LED_1, HIGH);
digitalWrite(LED_2, HIGH);
digitalWrite(LED_3, HIGH);
digitalWrite(LED_4, HIGH);
 }
}