Earlier quoted context omitted.
They are also really capable processors on their own with some nice I/O, and they can be integrated to be really low power so things can run on battery power for months to years.
Can they really last that long (on their own)? I looked into this when the ESP8266 first became popular maybe 4 years ago as I wanted to build WiFi temperature and humidity sensors. My calculations were that a set of AAA rechargable batteries (~2000mAh) would last a few days at most, with the device in deep sleep most of the time and waking up every 10 mins to take a reading and send it over WiFi. Right now I'm looki…
A bare chip makes it much easier, and you need to balance what comes online and how long it sleeps to still work in your use case.
It's not all that easy in some cases, but it can be done. I've used [1] as a resource before in my own projects.
[1] https://github.com/z2amiller/sensorboard/blob/master/PowerSa...