const int pinoLedVermelho = 8;
const int pinoInterruptor = 4;
const int pinoPIR = 3;

void setup() {
  pinMode(pinoLedVermelho, OUTPUT);
  pinMode(pinoInterruptor, INPUT);
  pinMode(pinoPIR, INPUT);
}

void loop() {
  int sinalLed = digitalRead(pinoPIR) 
              and digitalRead(pinoInterruptor);
  digitalWrite(pinoLedVermelho, sinalLed);
}