DCF77 Radio Time Signal

problem is the module starts a watch by itself, so your setInterval starts a watch every 2s, which might lead to the memory problem

but you can create a custom module locally (put it into modules folder and call it myDCF77 or something)

and use it this way

setInterval(function(){
    var watchId;
    var result = require('myDCF77').connect(B1, function(err, date, info) {
      if (err) {
        console.log("Invalid time received: " + err);
      }
      else {
        console.log('Date from DCF77 ' + date.toString());
        if(watchId) {
          clearWatch(watchId);
          watchId = undefined;
        }
      }
    });
    watchId = result.watchId;
  }, 1200000);

... the above needs a change inside the module as

exports.connect = function(dataPin, callback) {
  var dcf = {
    last : getTime(),
    bits : '',
    watchId: undefined
  };
  dcf.watchId = setWatch(function (e) {
    // Work out what bit we got
    var d = e.time-e.lastTime;
    var bit = (d<0.15)?0:1;
    // if we had a 2 sec gap then it's the beginning of a minute
    if (e.time - dcf.last > 1.5) {
      decode(dcf.bits, callback);
      dcf.bits = "";
    }
    dcf.last = e.time;
    // now add this bit of data
    dcf.bits += bit;
    if (dcf.bits.length>59)
      dcf.bits = dcf.bits.substr(-59);
  }, dataPin, { edge:"falling", repeat:true, debounce:75 });
  return dcf;
};

keep all other functions as is