#define sensorPin A1 
  int sensorValue = 0; 
  int led = 7;
  float voltage; 
  void setup()
{
pinMode(led, OUTPUT);
pinMode(sensorPin, INPUT);
Serial.begin(9600); 
delay(100); 
}
void loop()
{
sensorValue = analogRead(sensorPin); 
voltage = sensorValue * (5.0 / 1024); 
Serial.print("Tensão do potenciometro: "); 
Serial.print(voltage); 
Serial.print(" Valor: "); 
Serial.println(sensorValue); 
delay(500);
if((voltage)<2.5)
{
  digitalWrite(led, LOW);
}
else{
  if((voltage)>2.5)
  digitalWrite(led, HIGH);
}
}