Pre-requisites
Buy the components
Sleep for more than 1 hour using EEPROM to keep the count. Technically, this is not sleeping for more than 20 minutes, the maximum possible deep sleep, but it will keep a count every time it wakes up so that at the correct count, it will possibly enable the radio and do a desired task.
If only ESP8266 is used, short pin D0
to pin RST
to enable wakeup.