C++ Blynk (Legacy) - Code Examples for Basic Tasks

Projects made with Blynk
20

#9 Basic “Keeps running without WiFi or Blynk Server connection, but reconnects as soon as they are available” sketch

Simply does what the title says… Flashes the built in LED and sends UpTime data to both App and Serial monitor to show operation either way. Also has a lot of serial print commands to show general operation for troubleshooting… Remove them when you are comfortable that everything works for you.

#define BLYNK_PRINT Serial // This prints to Serial Monitor
#include <ESP8266WiFi.h>
#include <BlynkSimpleEsp8266.h>

#include <ESP8266mDNS.h>  // For OTA
#include <WiFiUdp.h>  // For OTA
#include <ArduinoOTA.h>  // For OTA

char auth[] = "xxxxxxxxxx";
char ssid[] = "xxxxxxxxxx";
char pass[] = "xxxxxxxxxx";
//char server[] = "xxx.xxx.xxx.xxx";  // IP for Local Cloud Server
char server[] = "blynk-cloud.com";  // URL for Blynk Cloud Server
int port = 8080;

int DeviceLED = 2;
int ReCnctFlag;  // Reconnection Flag
int ReCnctCount = 0;  // Reconnection counter

BlynkTimer timer;



void setup() {
  Serial.begin(115200);
  pinMode(2, OUTPUT);

  WiFi.begin(ssid, pass);  // Non-blocking if no WiFi available
  Blynk.config(auth, server, port);
  Blynk.connect();

  timer.setInterval(1000L, UpTime);

  ArduinoOTA.setHostname("Loss of connection test");  // For OTA
  ArduinoOTA.begin();  // For OTA
}



BLYNK_CONNECTED() {
  Serial.println("Cconnected");
  ReCnctCount = 0;
}




void UpTime() {
  Blynk.virtualWrite(V0, millis() / 1000);  // Send UpTime seconds to App
  Serial.print("UpTime: ");
  Serial.println(millis() / 1000);  // Send UpTime seconds to Serial
  digitalWrite(DeviceLED, !digitalRead(DeviceLED));  // Blink onboard LED
}



void loop() {
  timer.run();
  ArduinoOTA.handle();  // For OTA

  if (Blynk.connected()) {  // If connected run as normal
    Blynk.run();
  } else if (ReCnctFlag == 0) {  // If NOT connected and not already trying to reconnect, set timer to try to reconnect in 30 seconds
    ReCnctFlag = 1;  // Set reconnection Flag
    Serial.println("Starting reconnection timer in 30 seconds...");
    timer.setTimeout(30000L, []() {  // Lambda Reconnection Timer Function
      ReCnctFlag = 0;  // Reset reconnection Flag
      ReCnctCount++;  // Increment reconnection Counter
      Serial.print("Attempting reconnection #");
      Serial.println(ReCnctCount);
      Blynk.connect();  // Try to reconnect to the server
    });  // END Timer Function
  }
}

NOTE: And here is an enhanced version made by another Blynk Forum member :smiley:

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