How to arduino mega can work without internet

[XDUSS]

• My device Arduino Mega with Ethernet Shield W5100
PS. Sorry for my English…

Hi. How i can use arduino (+blynk) when without internet connection?
My program ends with “Blynk.begin”…
I managed to bypass it (code below) and everything works with and without Internet.
I would like if run arduino without internet,
then it connect to the blynk network immediately after detecting the connection to the Internet.
Code:

#define BLYNK_PRINT Serial

#include <SPI.h>
#include <SD.h>
#include <Ethernet.h>
#include <BlynkSimpleEthernet.h>

char auth[] = "xxx"; // Auth Token od Blynk
byte mac[] = { 0xDE, 0xAD, 0xBE, 0xEF, 0xFE, 0xED };

#define W5100_CS  10 //Ethernet shield pin
#define SDCARD_CS 4 //SDcard pin

BlynkTimer timer;



void setup()
{
  Serial.begin(9600);

  pinMode(SDCARD_CS, OUTPUT);
  digitalWrite(SDCARD_CS, HIGH); // Deselect the SD card
  Ethernet.begin(mac);
  Blynk.config(auth);

  if(Blynk.connect()){
    Serial.println("Connect");
  } else Serial.println("No connect");
  
  timer.setInterval(600000L, reconnect);
}

void loop()
{
  if(Blynk.connected()){ 
    Blynk.run();
  }
  Serial.println("Work");
  timer.run();
}

void reconnect(){
  if(!Blynk.connected()){
    Ethernet.begin(mac);
    Blynk.connect(1000);
  } else Serial.println("Connect OK");
}

Ok the code works (UP).
I have edited this post, maybe someone will need it.

[Gunner]

As per the directions, that you deleted in-order to post your topic… I have formatted your code for proper viewing.

Search this forum for other examples of functioning code without internet connection… many topics about this issue already.

[XDUSS]

For the needs of the project, I was editing the timeout in the Ethernet.h library so that the waiting time was not that long and other functions were running smoother.

timeout = 2000 (default 30000)
responseTimeout = 1000 (default 5000)

Ethernet.h file:

#ifndef ethernet_h
#define ethernet_h

#include <inttypes.h>
//#include "w5100.h"
#include "IPAddress.h"
#include "EthernetClient.h"
#include "EthernetServer.h"
#include "Dhcp.h"

#define MAX_SOCK_NUM 4

class EthernetClass {
private:
  IPAddress _dnsServerAddress;
  DhcpClass* _dhcp;
public:
  static uint8_t _state[MAX_SOCK_NUM];
  static uint16_t _server_port[MAX_SOCK_NUM];
  // Initialise the Ethernet shield to use the provided MAC address and gain the rest of the
  // configuration through DHCP.
  // Returns 0 if the DHCP configuration failed, and 1 if it succeeded
  int begin(uint8_t *mac_address, unsigned long timeout = 2000, unsigned long responseTimeout = 1000);
  void begin(uint8_t *mac_address, IPAddress local_ip);
  void begin(uint8_t *mac_address, IPAddress local_ip, IPAddress dns_server);
  void begin(uint8_t *mac_address, IPAddress local_ip, IPAddress dns_server, IPAddress gateway);
  void begin(uint8_t *mac_address, IPAddress local_ip, IPAddress dns_server, IPAddress gateway, IPAddress subnet);
  int maintain();

  IPAddress localIP();
  IPAddress subnetMask();
  IPAddress gatewayIP();
  IPAddress dnsServerIP();

  friend class EthernetClient;
  friend class EthernetServer;
};

extern EthernetClass Ethernet;

#endif

[Gfarid]

I want to do the same thing but new library 0.6.1 has different Ethernet.h . Could you help me to update accordingly.