code.txt

//   Place parameters below at the top of your code (or "include" from a separate CONFIG file)

// set SLEEP enable flag & duration
#define SLEEP_YES                  // UNcomment to enable 'light sleep' mode
#define uS_TO_S_FACTOR 1000000ULL  // Conversion factor for micro seconds to seconds
#define TIME_TO_SLEEP  120         // duration ESP32 will go to sleep (in seconds) (120 seconds = 2 minutes)




====================================================================================

//   Place the 3 lines below (#ifdef -> #endif) at the VERY BOTTOM of your code's main loop:

// +---------------------------------------------------------------------+//
// + MAINLOOP -----------------------------------------------------------+//
// +---------------------------------------------------------------------+//

void loop() {

//   EXISTING MAIN LOOP CODE GOES HERE
  
  #ifdef SLEEP_YES
    sleep_now();       
  #endif
}


====================================================================================


//   Place the following two functions below your code's main loop:

////////////////////////////////////////////////////////////////////////////////////////////////////////////
void sleep_now(){
  esp_sleep_enable_timer_wakeup(TIME_TO_SLEEP * uS_TO_S_FACTOR); // ESP32 wakes up every 120 seconds
  
  Serial.print("Going to light-sleep now for ");
  Serial.print(TIME_TO_SLEEP);
  Serial.println(" seconds...");
  Serial.flush(); 
  esp_light_sleep_start();

  print_wakeup_reason(); //Print the wakeup reason for ESP32

  delay(2000);

}

////////////////////////////////////////////////////////////////////////////////////////////////////////////
void print_wakeup_reason(){
  esp_sleep_wakeup_cause_t wakeup_reason;
  wakeup_reason = esp_sleep_get_wakeup_cause();

  switch(wakeup_reason)
  {
    case ESP_SLEEP_WAKEUP_EXT0 : Serial.println("Wakeup caused by external signal using RTC_IO"); break;
    case ESP_SLEEP_WAKEUP_EXT1 : Serial.println("Wakeup caused by external signal using RTC_CNTL"); break;
    case ESP_SLEEP_WAKEUP_TIMER : Serial.println("Wakeup caused by timer"); break;
    case ESP_SLEEP_WAKEUP_TOUCHPAD : Serial.println("Wakeup caused by touchpad"); break;
    case ESP_SLEEP_WAKEUP_ULP : Serial.println("Wakeup caused by ULP program"); break;
    default : Serial.printf("Wakeup was not caused by deep sleep: %d\n",wakeup_reason); break;
  }
}