const int botao = 34; 
const int rele = 12;  

void setup() {
  pinMode(botao, INPUT_PULLUP); 
  pinMode(rele, OUTPUT); 
}

void loop() {
  
  if (digitalRead(botao) == LOW)
  {
    
    digitalWrite(rele, HIGH);
  } 
  else 
  {
    
    digitalWrite(rele, LOW);
  }
}