Writing a Deep Sleep Sketch
To put your ESP32 into deep sleep mode and then wake it up, you need to write a sketch.
Configure the wake-up sources first. Configuring what will wake up the ESP32 is what this means. Use one wake-up source alone or mix many. We'll show you how to set a timer to wake you up in this post.
During deep sleep, you get to choose which peripherals to keep on or shut down. However, by default, the ESP32 powers down any peripherals that are not in use with the wake-up source you provide.
Finally, you use the esp_deep_sleep_start() function to put your ESP32 into deep sleep mode.
Timer Wake Up
The ESP32 may enter deep sleep mode and then wake up at predefined times. This functionality is very useful if you are running projects that require time stamping or daily tasks while using little electricity.
Read the full article: https://lededitpro.com/esp32-timer-wake ... duino-ide/