touch_pad_t pin = esp_sleep_get_touchpad_wakeup_status();
switch(touchPin) {
  case 0  : Serial.println("Touch detected on GPIO 4"); break;
  case 1  : Serial.println("Touch detected on GPIO 0"); break;
  case 2  : Serial.println("Touch detected on GPIO 2"); break;
  case 3  : Serial.println("Touch detected on GPIO 15"); break;
  case 4  : Serial.println("Touch detected on GPIO 13"); break;
  case 5  : Serial.println("Touch detected on GPIO 12"); break;
  case 6  : Serial.println("Touch detected on GPIO 14"); break;
  case 7  : Serial.println("Touch detected on GPIO 27"); break;
  case 8  : Serial.println("Touch detected on GPIO 33"); break;
  case 9  : Serial.println("Touch detected on GPIO 32"); break;
  default : Serial.println("Wakeup not by touchpad"); break;
}