Your project has come to a stand still. Your brain has come to a dead end... you can't remember that specific connection that'd you had once seen- which would be perfect for your application... it's all you need to get to the finish line...
It's a joint where 1 side rotates and the other is the base. An electronic signal, power needs to go through there but you can't just use a cable or wires... the thing rotates 360 degrees if not till infinity. A cable/ physical wire would wind itself till it'd snap/ break/ cause a short... you've seen it before- a electronic connector that incorporates itself into the rotating section. You know what it looks like, but not the name of it.... Google searching is frivolous.
No problem! Because to your rescue, we have the amazing resource which is Connector Book found at https://connectorbook.com/
You can search by image/ photo... by identification, by brand, by logo... and every and any electronic connection is contained in this extensive resource- there are even non- electrical connectors- on the lines of different RF connections as an example.
Feel free to leave a comment with your guess or if you've located the connection type I'd described above.