All the parts, build instructions, design theory, code, and anything else you could ever need can be found in the link below for free:
https://www.roboticworx.io/p/build-a-one-handed-soldering-tool
(If there is a pop-up, just simply click "DISMISS" at the bottom.)
Here are the demos that were linked earlier:
SO COOL!!!! This would be a life saver whenever I have to solder pin headers.