In a microcontroller powered by a solar cell we need to have the current time. When the sun decrease the micro-controller switch off and all the volatile data vanish. When the sun increase the micro-controller reboot and we need to set the time on reboot.
I had an idea but I do not know enough wifi to be sure it's feasible : Getting the current time from the surrounding wifi signals.
In this post How much information can be gathered about a network without connecting? you can get :
- ESSIDS BSSIDS
- Crypto strength and authentication scheme (Pre shared Key vs EAP/Radius)
- Signal strength
But I can't see if the AP current time is obtainable ?