@wanek I have implemented the code you suggested and made the changes in the Blynk library file. It works well for me. Thanks again for the solution.
i’m glad that could help.
I am facing same problem.I am using Nodemcu ESP8266 12e.
This my original code
#define BLYNK_PRINT Serial // Comment this out to disable prints and save
#include <ESP8266WiFi.h>
#include <BlynkSimpleEsp8266.h>
#include <SimpleTimer.h>
#include <TimeLib.h>
// You should get Auth Token in the Blynk App.
// Go to the Project Settings (nut icon).
char auth[] = "xxxxxxxxxxxxxxxxxxx";
// Set your LED and physical button pins here
const int ledPin = 16;
const int btnPin = 5;
SimpleTimer timer;
void checkPhysicalButton();
int ledState = LOW;
int btnState = HIGH;
void sendUptime() {
Blynk.virtualWrite(V20, millis() / 60000);
long rssi = WiFi.RSSI();
Blynk.virtualWrite(V15, rssi);
}
void setup()
{
Serial.begin(115200);
pinMode(ledPin, OUTPUT);
pinMode(btnPin, INPUT_PULLUP);
digitalWrite(ledPin, ledState);
timer.setInterval(100L, checkPhysicalButton);
Blynk.begin(auth, "xxxxxxx", "xxxxxxx");
while (Blynk.connect() == false) {
// Wait until connected
}
timer.setInterval(60000L, sendUptime);
// Setup a function to be called every 100 ms
}
bool isFirstConnect = true;
// This function will run every time Blynk connection is established
BLYNK_CONNECTED() {
if (isFirstConnect) {
Blynk.syncAll();
isFirstConnect = false;
}
}
// When App button is pushed - switch the state
BLYNK_WRITE(V2) {
ledState = param.asInt();
digitalWrite(ledPin, ledState);
}
void checkPhysicalButton()
{
if (digitalRead(btnPin) == LOW) {
// btnState is used to avoid sequential toggles
if (btnState != LOW) {
// Toggle LED state
ledState = !ledState;
digitalWrite(ledPin, ledState);
// Update Button Widget
Blynk.virtualWrite(V2, ledState);
}
btnState = LOW;
} else {
btnState = HIGH;
}
}
void loop()
{ timer.run();
Blynk.run(); // Run Blynk
// Run SimpleTimer
}
I have tried your code but got many errors. can explain how to implement this your my code???
I am using Nodemcu ESP 8266 12e.
What errors did you get?
The above code works fine when it connected to internet .
But doesn’t works when wiffi router is off.
I have connected physical buttons they should works when internet is off / wiffi router is off.
Plz guys help me.
Hi,
Did you ever get your arduino Sketch to run when Blynk is not connected to the internet?
No ,i don’t get.
I was is search of this but know i’m working on different project.
It’s a little more complicated than it first seems but the 2 basic steps are:
'1. Bail out of the while loop that you MUST have in setup()
int mytimeout = millis() / 1000;
while (Blynk.connect() == false) {
if((millis() / 1000) > mytimeout + 8){ // try for less than 9 seconds
break;
}
}
'2. Only process blynk.run() in the main loop() when you are connected.
if(Blynk.connected()){
Blynk.run();
}
Further requirements are SimpleTimer to check if router / server is now running so a connection to Blynk can be made etc.
HTH
2 Likes
Hi, I’m new to blynk and not that good with codes…
I copy/paste your codes and added the libraries (i got them
from the blynk ethernet sample)
#define BLYNK_PRINT Serial
#include <SPI.h>
#include <Ethernet.h>
#include <BlynkSimpleEthernet.h>
I’m using W5100
I did the changes to the blynk library
Getting the error:
‘beep’ was not declared in this scope
Am I missing any libraries or something?
Any help would be great! (Emphasis on “im no good at coding”) 
beep() is a standard Arduino function so I don’t know why you have a problem with it.
Just comment the line out for now and proceed with out.
hello!
beep() is just a function i declared somewhere else, in my sketch, it is used to generate buzzer sounds, if an event occurs.
as costas said, you can safely delete them, no problem. otherwise, the code should work. i’m using this in a home automation project, the arduino have to run continuously, even when there is no internet connection, because the physical light switches are wired to the arduino.
Got it, i commented out all the beep, now I got a new error:
‘updateBlynk’ was not declared in this scope
really sorry for stupid questions. I’m just totally bad at this, but your code is the exact thing I need for my project. 
I think I should not comment it out (looks important i guess), but when I did (just for the sake of uploading) the device was not able to connect (but it kept on trying though)
any thoughts? (I can connect fine when i use the default sample files (ethernet & usb)
your code is missing some { or } or these are in the wrong spot/s.
ok, please copy paste your sketch here, without modifying anything (remove token of course )
Hi again guys, the project was abandoned for some time, but for the couple of the last days I’ve back to the code and this thread and came with this code (NodeMCU, ESP8266):
#define BLYNK_DEBUG // Optional, this enables lots of prints
#define BLYNK_PRINT Serial
#include <ESP8266WiFi.h>
#include <BlynkSimpleEsp8266.h>
#include <SimpleTimer.h>
const char* espHostname = "ESP_HOSTNAME";
const char* ssid = "AP_NAME";
const char* password = "AP_PASSWORD";
const char* host = "BLYNK_SERVER_IP";
const char auth[] = "BLYNK_AUTH";
const int checkInterval = 30000;
const int butPin = D3;
const int ledPin = D4;
const int relPin = BUILTIN_LED;
int x = 0; // start as OFF
int butState;
int oldButState;
SimpleTimer timer;
void blynkCheck() {
if (WiFi.status() == 3) {
if (!Blynk.connected()) {
Serial.println("WiFi OK, trying to connect to the Blynk server...");
Blynk.connect();
}
}
if (WiFi.status() == 1) {
Serial.println("No WiFi connection, offline mode.");
}
}
void setup()
{
pinMode(butPin, INPUT); //Button for turning on the light
pinMode(ledPin, OUTPUT); //LED on when relay is off, and backwards
pinMode(relPin, OUTPUT); //Relay
digitalWrite(relPin, HIGH);
digitalWrite(ledPin, LOW);
Serial.begin(9600);
WiFi.hostname(espHostname);
WiFi.begin(ssid, password);
Blynk.config(auth, host);
timer.setInterval(checkInterval, blynkCheck);
}
void loop()
{
timer.run();
if (Blynk.connected()) Blynk.run();
butState = digitalRead(butPin);
if (butState == HIGH && oldButState == LOW) {
if (x == 1) { //ON
digitalWrite(relPin, LOW);
digitalWrite(ledPin, HIGH);
Blynk.virtualWrite(V0, HIGH);
x = 0;
}
else { //OFF
digitalWrite(relPin, HIGH);
digitalWrite(ledPin, LOW);
Blynk.virtualWrite(V0, LOW);
x = 1;
}
}
oldButState = butState;
}
BLYNK_WRITE(V0)
{
int val = param.asInt();
digitalWrite(ledPin, val);
digitalWrite(relPin, !val);
x = !x;
}
BLYNK_CONNECTED()
{
Serial.println("Reconnected, syncing with cloud.");
Blynk.syncAll();
}
So that’s the code “as is” for my project (controllable light switch for the room). It have controllable interval of checking the connection here:
const int checkInterval = 30000;
After booting it works for 30000ms (30 seconds) with offline mode, then trying to connect.
If WiFi connected and Internet is ok, it works well, with reconnects to the blynk server every 30 seconds.
If WiFi is available, but have no internet — it stucks for ~10 seconds then working offline, till another timer call.
If no WiFi connection — it doesn’t try to connect to the Blynk, just logging to the console and goes offline.
The default 30 seconds interval is nice for debug, but for real-world working consider setting it for 300000 or 600000 (5-10 minutes).
1 Like
hello sir i tried ur code it works good when its connected .
when I unpluge the internet cable the physical buttons works very good no freeze.
but when I reconnect the internet cable the blynk wont reconnect again , can u plz guide me how to do that .
this is my code
#define BLYNK_PRINT Serial // Comment this out to disable prints and save space
#include <ESP8266WiFi.h>
#include <BlynkSimpleEsp8266.h>
// You should get Auth Token in the Blynk App.
// Go to the Project Settings (nut icon).
char auth[] = "xxf";
char ssid[] = "dannamo";
char pass[] = "loxx8";
int switchPin = D1;
int ledPin = D2;
boolean lastButton = LOW;
boolean currentButton = LOW;
boolean ledOn = false;
void setup()
{
Serial.begin(9600);
Blynk.begin(auth, ssid, pass);
pinMode(switchPin, INPUT);
pinMode(ledPin, OUTPUT);
int mytimeout = millis() / 1000;
while (Blynk.connect() == false) {
if((millis() / 1000) > mytimeout + 8){ // try for less than 9 seconds
break;
}
}
}
boolean debounce(boolean last)
{
boolean current = digitalRead(switchPin);
if (last != current)
{
delay(5);
current = digitalRead(switchPin);
}
return current;
}
BLYNK_WRITE(V10) //Function to test status from BLYNK widget to PHOTON
{
int state = param.asInt();
if (state ==1)
{
ledOn = !ledOn;
}
else if (state ==0)
{
digitalWrite(ledPin,ledOn);
}
}
void loop()
{
currentButton = debounce(lastButton);
if (lastButton == LOW && currentButton == HIGH)
{
ledOn = !ledOn;
}
lastButton = currentButton;
digitalWrite(ledPin, ledOn);
if(Blynk.connected()){
Blynk.run();
}
//Blynk.run();
}@dananmo you need this bit
Study the many SimpleTimer examples and then decide how often you want to check if an internet connection is available. The function you then need to call from SimpleTimer would be something like this:
void reconnect(){
int mytimeout = millis() / 1000;
while (Blynk.connect() == false) {
if((millis() / 1000) > mytimeout + 8){ // try for less than 9 seconds
break;
}
}
}
thank u very much sir u were very helpful thanks again now its working good thanks
Ηι @Costas!! please I need your advise…
When im using
Blynk.config(auth);
Blynk.connect(3333);
the result on serial monitor is always this:
[0]
___ __ __
/ _ )/ /_ _____ / /__
/ _ / / // / _ / '/
///_, /////_
/__/ v0.4.4 on Arduino Mega
[5001] Connecting to blynk-cloud.com:8442
[10002] Connecting to blynk-cloud.com:8442
[15003] Connecting to blynk-cloud.com:8442
[20004] Connecting to blynk-cloud.com:8442
[25005] Connecting to blynk-cloud.com:8442
[30006] Connecting to blynk-cloud.com:8442
[35007] Connecting to blynk-cloud.com:8442