Can I write a paper on software that I published a year ago? I am a bachelor-level (software engineering) student. I made a GitHub repository more than a year ago, where I use machine learning and deep learning to identify movements in accelerometer signals.

As of now, the GitHub repository has a thousand stars. There is already research being made derived from my work. As a practical example, here I collaborated with someone to write a paper.

I wonder: Should I write and publish a paper on the first project, even though it's a year old? What are my options, if any?
Yes, you can publish a paper, if 


you have new ideas in your software that you developed yourself.
the ideas have not been published by you before.


If other people who have used your software also documented your ideas, cite them.