Recover old state after powerdown/ reset

[michapr]

Hi,

If using the device with a ESP32 and deep sleep for saving energy the gas index algorithm will not work because all collected values lost - as far as I understand.
Same will happen if power is down (as sample replace battery or empty LiPo).

Can you provide any example code for save / restore the states to EEPROM?
For ESP32 deep sleep it could be modified later for RTC RAM - and maybe once every hour save to EEPROM or maybe use external FRAM.

THANKS!