MG-811 CO2 sensor

...what about:

function measureAndLog() {
  var value;
  // your measuring and calculation assigning result to value
  console.log("CO2 measured: " + value + " [ppm]");
};

function cycle(){
  console.log("waiting...");
  setTimeout(function(){
    measureAndLog();
    cycle();
  },300000); // 300'000[ms] = 5 [min]
}

cycle();