I downvoted your comment, but then noticed that you have only made two comments here, so this felt needlessly cruel. So I upvoted your first comment as recompense. Your first one was a fine comment. This one is not.
I'd be glad to hear more about using this technique to check alignment of floppies. In fact, the top rated comment on this page is about that. But saying "Nothing new here" is unwarranted and crass. While this may be old hat to you, it's interesting to many who might not have considered it.
Perhaps more importantly, only the first part of the article is about visually checking the magnetic strip. The rest is about enhancing it using image enhancement, decoding it by guessing likely parity codes, and then detailing years of unsuccessful attempts to discourage people from buying this fraudulent product.
Anyway, welcome to HN and please stick around to share your experience by make more comments like your first one.
