I am running a cluster of Pi3 and Pi4. Each node runs on a battery and is powered by a solar panel, in a remote area like a farm with no grid. Pis are connected to each other by WiFi in a local network. I have a program running on a controller/manager Pi in this cluster that sometimes turns a Pi off to save energy. But, I have no idea how to turn Pis on?
One possibility is to ask the Pi to turn itself on every X minutes and ask the controller if it is time to be back!
Another possibility is that the Pi benefits from an attached microcontroller that has a battery itself and WiFi. The controller Pi can communicate with this to turn the Pi on!
Another possibility is to signal the Pi to turn on.
However, I have no idea how to achieve any of these or a different solution.
ask the Pi to turn itself on every X minutes
- you may as well ask your toaster to turn itself on - best bet is a battery powered microcontroller with wifi (ESP32/ESP8266 comes to mind), and have that turn the pi on (relay? reset? GPIO3?) somehow - there's no method for a pi to turn itself on, as it has as much ability to do so as a toaster as I previously mentioned