ESP8266NodeMCU - how to restart wifi after a disconnect

Projects General Guidance
1

I have a Lolin NodeMCU set up to repeatedly ping devices on my local network, and on the web.
It uses the ESP8266WiFi library.

Until there is a disconnect it works fine; however I cant see how to get it to reconnect.

The full project is described here

and the relevant bits of the sketch - I've attached the full sketch below for context but its quite big.

#include <ESP8266WiFi.h>            //WiFi functions

..

WiFiEventHandler gotIpEventHandler, disconnectedEventHandler;

..

and in setup()

 //monitor Wifi connection and handle D0

  gotIpEventHandler = WiFi.onStationModeGotIP([](const WiFiEventStationModeGotIP & event)
  {
    Serial.print("Station connected, IP: ");
    Serial.println(WiFi.localIP());
    digitalWrite(dPin[1], 0); //blue LED
  });

  disconnectedEventHandler = WiFi.onStationModeDisconnected([](const WiFiEventStationModeDisconnected & event)
  {
    Serial.println("Station disconnected");
    digitalWrite(dPin[1], 1); //blue LED
  });

  bool stationConnected = WiFi.begin(ssid, pass);
  delay(200); //allow time to connect
  // Wait until connection completed
  Serial.print("Connecting to AP...");
  while (WiFi.status() != WL_CONNECTED)  {
    delay(200);
    Serial.print(".");
  }
  Serial.println("Ok\n");
  digitalWrite(dPin[0], 0); //indicate wifi connected -  white LED

I've googled & read the documentation but to me its advanced gobbledegook.

netmonitor-good.ino (18.2 KB)

2

Put the code starting the Wifi in a function of its own. Call that function from setup but also from the code, in loop, where the failure is detected.

3

Thanks RailRoader, AFAIK the failure is detected by the disconnectedEventHandler - not in the loop().

4

Here's a code that I use to maintain a WiFi and MQTT connection, perhaps it will give a few hints.

Also, if you have the ESP8266 with OS you can set the keep alive as a separate task.

void MQTTkeepalive( void *pvParameters )
{
  // setting must be set before a mqtt connection is made
  MQTTclient.setKeepAlive( 90 ); // setting keep alive to 90 seconds makes for a very realiable connection, must be set before the 1st connection is made.
  for (;;)
  {
    //check for a is connected and if the WiFi thinks its connected, found checking on both is more reliable than just a single check
    if ( (wifiClient.connected()) && (WiFi.status() == WL_CONNECTED) )
    {
      xSemaphoreTake( sema_MQTT_KeepAlive, portMAX_DELAY ); // whiles loop() is running no other mqtt operations should be in process
      MQTTclient.loop();
      xSemaphoreGive( sema_MQTT_KeepAlive );
    }
    else {
      log_i( "MQTT keep alive found MQTT status %s WiFi status %s", String(wifiClient.connected()), String(WiFi.status()) );
      if ( !(WiFi.status() == WL_CONNECTED) )
      {
        connectToWiFi();
      }
      connectToMQTT();
    }
    vTaskDelay( 250 ); //task runs approx every 250 mS
  }
  vTaskDelete ( NULL );
}

You can have your WiFi feedback routine either try a reconnect or a reset of the ESP8266 to start all over.

Also, you might want to issue a WiFi.disconnect(); before making the connection:
As shown below:

void connectToWiFi()
{
  byte mac[6];
  log_i( "connect to wifi" );
  while ( WiFi.status() != WL_CONNECTED )
  {
    WiFi.disconnect();
    WiFi.begin( SSID, PASSWORD );
    log_i(" waiting on wifi connection" );
    vTaskDelay( 4000 );
  }
  log_i( "Connected to WiFi" );
  WiFi.macAddress(mac);
  log_i( "mac address %d.%d.%d.%d.%d", mac[0], mac[1], mac[2], mac[3], mac[4], mac[5]  );
  WiFi.onEvent( WiFiEvent );
  GetTheTime();
  printLocalTime();
}
5

johnerrington:
Thanks RailRoader, AFAIK the failure is detected by the disconnectedEventHandler - not in the loop().

Call a restart from there then?