I've been working on a similar hobby project for a bit--does anybody know of a good QR or similar tag tracking library? At my old lab we used April tags, but I'

I've been working on a similar hobby project for a bit--does anybody know of a good QR or similar tag tracking library? At my old lab we used April tags, but I'd prefer something better maintained and easier to set up. ARToolkit doesn't seem to be well maintained right now either. :(