VSS NO ARDUINO

VSS (VEHICLE SPEED SENSOR) NO ARDUINO COM 4N25




1 x 4N25
2 x resistor 4k7
1 x diodo 1n4148
1 x VSS AUTOMOTIVO 3 fios

código
===
int pino = 11;
int led = 13;
int old;
int valor;

void setup(){
  Serial.begin(115200);
  Serial.println("inicio");
  pinMode(pino, INPUT);
  pinMode(led, OUTPUT);
}


void loop(){
  valor = digitalRead(pino);
  if(valor != old){
    Serial.println( valor);
    if( digitalRead(pino) ){
      digitalWrite(13, HIGH);
    }else{
      digitalWrite(13, LOW);
    }
    old = valor;
  }

}
===
volatile int iIRQ2_Count;
int IRQ2_PIN = 2;
int IRQ2_IRQ = 0;

void setup(){
  // Put your setup code here, to run once:
  Serial.begin (9600);
  attachInterrupt(IRQ2_IRQ, IRQ2_Counter, RISING);
  delay(25);
  detachInterrupt(IRQ2_PIN);
  Serial.print(F("Counted = "));
  Serial.println(iIRQ2_Count);
}

void IRQ2_Counter() {
  iIRQ2_Count++;
}

void loop() {
  Serial.println(iIRQ2_Count);
  iIRQ2_Count = 0;
  delay(1000);

}