About 5 years ago I started trying to build this exact thing. I wrote some code, printed some gears and attached them to servos, assembled some hall effect sensors onto the whole thing, and then stopped.
I had a camera that I could command to an azimuth and an elevation. I think it was a PlayStation3 pseye camera.
It certainly would not have been able to zoom in to the point that this one seems to be able to.
I was going to use my RTL SDR to listen to the ADSB and mount the whole thing on my roof under a clear plastic dome.
Easiest today would be to use the project this project uses. I don't think it existed at the time I was trying, though. And, yes, that would be easier, but not in the vein of "doing it myself" that I was aiming for. :D
