GATT service on RuuviTag

You're not really supposed to re-use UUIDs for different things, so the Bluetooth SIG suggests you should use a totally random 128 bit UUID (the chances of duplicates and then basically nothing).

So, go to a site like this and get a random UUID - for instance:

123fd926-40c3-4cf3-9797-9a8703e32795

Then just change the second group of 4 for all your services and characteristics, eg:

123f0001-40c3-4cf3-9797-9a8703e32795
123f0002-40c3-4cf3-9797-9a8703e32795
123f0003-40c3-4cf3-9797-9a8703e32795
123f0004-40c3-4cf3-9797-9a8703e32795

So then you have:

NRF.setServices({
  "123f0001-40c3-4cf3-9797-9a8703e32795": {
    "123f0002-40c3-4cf3-9797-9a8703e32795": {
      notify: true,
      value : [Math.round(E.getTemperature())],
    }
  }
});
setInterval(function () {
  NRF.updateServices({
    "123f0001-40c3-4cf3-9797-9a8703e32795": {
      "123f0002-40c3-4cf3-9797-9a8703e32795": {
        value : [Math.round(E.getTemperature())],
        notify: true
      }
    }
  });
}, 1000);

And you're sorted.

The only gotcha is advertising 128bit UUIDs is hard since they use up a lot of your available space for advertising - so honestly I'd avoid that and would instead try to find your device based on its name (which you can easily change).