I had a close friend with T1D who asked me to help him set up, and dial in a closed loop APS about two years ago. I took a deep dive into it and found it to be much, much more complicated than the PID type regulation I was expecting it to be. Plus, if I made a mistake, he might die. So I declined out of fear.

Unfortunately he did die just last March, alone in his apartment after slipping into a coma. His pump kept right on pumping him straight to his grave because the feedback loop of the system required human intervention, even if the human is incapacitated.

I wish I would have taken the risk, and I do hope this complicated, but solvable problem will be, and the solution made available to those who need it.