One thing I believe that's not being properly considered is the fact this is really a multilevel problem - if you want to make a smart IoT device you still wan

One thing I believe that's not being properly considered is the fact this is really a multilevel problem - if you want to make a smart IoT device you still want a reliable device. "On top of" is absolutely the best concept. Yes, the biggest computational bang for the buck comes from stuffing linux or something similar in, but who doesn't react with a smile when they see a multi year uptime reported - it's not rare, but it's not anywhere near a majority either - Start with the basic circuit, on top of that you add microcontroller logic to mediate between the higher level ARM SoC or whatnot and the base circuit, and just as importantly, you've also got a microcontroller based watch dog that will kick linux if it falls over. My experience in building this https://hackaday.io/project/21966-quamera https://hackaday.io/project/21966-quamera is to never stop asking "Quis custodiet ipsos custodes" (anybody proffering analog solutions will be ignored, analog is hard and I am stupid)