Can one expect the patent examiner to know that an 'IOT sensor' is a sensor that communicates to a computer that is networked into a LAN or WWAN?
No one here can answer whether a future examiner will be familiar with a given term. There are so many examiners which such a range of knowledge and experience.
However, the fact that you are asking the question suggests that the term has not reached the point that an examiner (let alone the person of ordinary skill in the art) would necessarily be aware of it. In such a case, the prudent thing to do is to include a definition in the description. Because what is the downside of doing so?
1This confirms what I thought the answer would be: I was uncertain if I would be insulting the examiner by describing it. Thanks Apr 9, 2018 at 4:34
1@gatorback An examiner will probably not even read your description unless there is an issue of what a term means, so you shouldn't worry about that. By way of illustration of how elementary your description might be, it's still quite common for computer-implemented inventions to include description about how a computer includes a processor and memory.– MacaApr 9, 2018 at 4:36
You will describe it, and give examples, in your specification and drawings. Then you can use it the term in your claims if it makes sense.