Authorship dispute on a paper that came out of a final report of a course?
While it's impossible to judge contribution from outside, I generally recommend erring on the side of inclusion when it comes to authorship.  If there's a reasonable argument that somebody contributed, it doesn't really cost you anything to have them on the paper.

Furthermore, there are many ways to contribute to a paper (see, for example, the CRediT taxonomy), and many journals even require a contributions section in which you can explain who exactly did what. In this case, it sounds like you wrote the paper, designed the system, built the system, and both of you ran experiments. You can't ethically "undo" somebody's experimental work by redoing it yourself.  

What you should never do is to drop somebody from authorship without consulting them. You had a draft with this person on it as an author, and even if they never got back to you, for all they know they're still a co-author. Probably it doesn't matter to them very much (or else they'd likely have gotten back to you), but it's still unethical to remove somebody from authorship without their consent. It is also unethical to submit a paper without the consent of all of the authors, so that's also a potential problem in this situation, where you're just kinda doing what you feel like without consulting with anybody else.

In fact, the basic problem I see here is that you seem to be operating without any advice from somebody who can help you navigate these questions (as well as the issue of quality, which I won't touch otherwise). Your advisor is likely a good source of such advice, and even if you don't like/trust your advisor, you should be able to find somebody who knows the scientific world well who can be a mentor for you.