How to avoid crossing my advisor if I write a paper as a sole author? A bit of a controversial question here. I am a PhD student currently away from campus on an internship in another state (in the US). I left campus with my advisor-provided laptop and some dataset I collected while working in my advisor's lab. We had the mutual understanding that me taking the official lab's laptop to the place of my internship was in the spirit of me being able to do my research effectively while I am away from campus.

For the past four months, I have been working at my leisure hours at my place of internship and during weekends to investigate an algorithm with respect to the dataset I collected while working under my advisor -- in his lab. I should mention that since I am away on an internship, I am not his Research Assistant at least for now (until I return to campus). 

Aside from using the dataset I collected from his lab, I have scraped publicly available datasets from other research labs online and used them to rigorously test my algorithm. My algorithms are starting to yield promising results which I think are about right for a publication. Because my advisor has made little or no contribution to my work so far, I am not sure how appropriate it is to put his name on the paper I am writing which reports my findings so far. I have tacitly brought this up with him in emails  so far but he has not expressed any enthusiasm about whatever work I am doing remotely (perhaps he doesn't trust what he hasn't seen?). 

Since the deadline of the conference is coming up soon, how would you suggest I do not cross him if I write the paper as a sole author?
If you don't know whether your advisor expects to be a co-author or not, just ask him.

If you feel that the advisor shouldn't be a co-author, you can present that as the "default":


  I am planning to write up my work with X, to submit to conference Y. You haven't really been involved in this work so far, so I guess you won't co-author this paper with me. Is that right?


If based on the specifics of the situation you don't have any strong feelings against co-authoring this paper with him, but you just aren't sure what he wants, you can just ask him:


  I am planning to write up my work with X, to submit to conference Y. Are you interested in co-authoring this paper with me?


As you have said, you can't read minds. The only way to know what's in his, is to communicate. 

And it's really important that you have this discussion as soon as possible; authorship disputes are much trickier to resolve after publication (when they can potentially lead to retraction) than before submission.