I read the walkthrough that you linked but that didn’t help. It described how to buy the detector andwhere to find the battery, both of which I had already done, but it does not say what to do with the detector.
In fact, I still have the detector and battery as separate items, the description of the detector says that it needs batteries but I’ve not encountered anything that causes the batteries to be inserted.
So my question remains, is the detector needed for this update or is it simply being collected for use in future updates?