This August 8, 2018, Bloomberg Businessweek story explains well how do-it-yourself looping works.
This story, set from the perspective of Kate Farnsworth and her 15-year T1D daughter, Sydney, provides a great explanation of how the DIY movement emerged and how it’s made a difference in people’s lives. Kate and her daughter live in the Toronto area.
Kate is one of the frequent responders on the Facebook group, Looped, who generously help people get their DIY systems set up as well as on-going maintenance. I follow this group to help me keep up with Loop, the system that I use. I am continually amazed at the technical competence and selfless spirit shown in this group.
I started on the Apple-based Loop system in November of 2016. I would not willingly use any other commercially-based system at this time. Other looping systems include OpenAPS and AndroidAPS.
Getting a loop-able older pump remains the toughest hurdle to setting up one of these systems at this time. People do continue to find these pumps, however.
Here are links to the documents that detail system requirements and set-by-step instructions.