Extended documentation for deep-sleep

docs/advanced-usage/deep-sleep.md

@@ -1,13 +1,20 @@
-Before deep sleeping, you will want to ensure that all messages are sent, including the `$online →  false`. To do that, you can call `Homie.prepareToSleep()`. This will disconnect everything cleanly, so that you can call `ESP.deepSleep()`.
+Before deep sleeping, you will want to ensure that all messages are sent, including property values of your `HomieNode` and the `$online →  false`. To do that, you can call `Homie.prepareToSleep()`. But the event `MQTT_READY` is emitted before your `HomieNode`s `loop()` method is called. Therefore you need to postpone the call to `Homie.prepareToSleep()` until the `loop()` method of all `HomieNode`s is called and their properties are submitted over MQTT. For that the additional Timer is necessary. Then `Homie.prepareToSleep()` will disconnect everything cleanly, so that you can call Homie.doDeepSleep()`.
 
 ```c++
 #include <Homie.h>
+#include "Timer.h"
+
+Timer t;
+
+void prepareSleep() {
+  Homie.prepareToSleep();
+}
 
 void onHomieEvent(const HomieEvent& event) {
   switch(event.type) {
     case HomieEventType::MQTT_READY:
-      Homie.getLogger() << "MQTT connected, preparing for deep sleep..." << endl;
-      Homie.prepareToSleep();
+      Homie.getLogger() << "MQTT connected, preparing for deep sleep after 100ms..." << endl;
+      t.after(100, prepareSleep);
       break;
     case HomieEventType::READY_TO_SLEEP:
       Homie.getLogger() << "Ready to sleep" << endl;
@@ -25,5 +32,6 @@ void setup() {
 
 void loop() {
   Homie.loop();
+  t.update();
 }
 ```