The duplicate detector is left weak like that on purpose to allow for reposts of good stories that didn't get significant attention the first time they were posted. This is described in the FAQ: https://news.ycombinator.com/newsfaq.html.

We treated this one as a dupe because it's pretty hard to argue that the previous post didn't get significant attention at 46 points. On the other hand, the interest in this project (including the repost) looks organic and genuine, so as an experiment, we've unburied it and merged yesterday's comments into this thread.