Smart lamp blynk+esp8266

Hello, everyone;
I’m new to the community; I’ve already read a lot of discussions and taken parts of code to make some of my projects with blynk;

In my last project I’m having some whims with the connection to the blynk server; I’d like a help to understand how to solve the problems;

Here is a description of the whole project:

Circuit PCB:

At first, I had a very strange behavior with esp, from the blynk app appeared the notification that esp was offline, and the output pins changed state; it happened several times in 2 days, so I had light on unintentionally…
The RSSI wifi value was about -80dBm (the router is about 5mt away and is separated by only 1 wall)

I thought of changing esp, I took another esp and replaced , the value of RSSI fell to -50dBm
Since last night no strange problem of change of state of output ;

After about 5 minutes appeared esp disconnect notification from blynk app; then I think through the pc to send ping to esp to understand if it is a device reset or a problem on the server side so I do: ping -t 192.168…
the answer always happens with a time of about 3ms, very fast.
I wait as long as after about 20 minutes returns the app to give notification of disconnection, but the ping has always had a positive response.
Closed the ping so as not to occupy the esp in useless answers.

This morning at 8:35 a.m. notification blynk app esp offline until 10:35 a.m.; I switch off the power supply and it restores quickly.

May be problems due to the very low delay() inside the code ?
Is the server where I connect correct?
Can the cili timer.setintervall of 100L duration be a problem? They are the control of the buttons on the wall.

Details Hardware :
• NodeMCU V2 (ESP12E) - Wifi
• Router Fritzbox 3490
• Smartphone Android Xiaomi MI 9T
• Blynk server
• Blynk Library version 0.6.1

The project foresees that the chandelier can be controlled by blynk apps for smartphones, and by 2 buttons on the wall.

The controls to drive the chandelier from the blynk app are 3:
-On or off (also with timer)
-Change of brightness
-Deactivation or activation of the LEDs installed at the bottom. To have only indirect light bouncing from the ceiling.

There are 2 controls on the wall:

-Button for on/off control
-Button for changing brightness

to improve the chandelier and make it more “smart”, a DHT22 sensor has been inserted to control the temperature and humidity of the room.

During the connection time of the esp, (about 5-8 seconds) it is not possible to manage the buttons on the wall; if the connection to the server is not established,
a timer of 30sec is activated that allows to use the buttons on the esp.


     USE PIN ESP8266:
    PIN D2 - NOT USE
    PIN D3 - NOT USE
    PIN D4 - OUTPUT Relay led down ON/OFF
    PIN D5 - INPUT Pushbutton DIMMER (pulldown 10kohm) 
    PIN D8 - INPUT Pushbutton ON/OFF (pulldown 10Kohm)
     USE PIN APP_Blynk:
     V1 = RSSI Widget wifi power (GAUGE)
     V2 = ON-OFF Widget ALIM LED_Sync pushbutton D8  (BUTTON)
     V5 = Temperature DHT22 (GAUGE)
     V6 = Humidity DHT22 (GAUGE)
     V7 = Connection status ESP8266
     D2 = Relay led down ON/OFF (BUTTON)

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#include <ESP8266WiFi.h>
#include <BlynkSimpleEsp8266.h>
#define BLYNK_PRINT Serial
#include <DHT.h>

#define VPIN V2
#define VPIN1 V1
#define DHTPIN D7
#define DHTTYPE DHT22

WidgetLED led1(V7); //connection status led widget

char auth[] = "dNqLnA0MTYweGy_Jz04M_3yuT1U0uYRj"; //token blink app
char ssid[] = "FRITZ Claudio"; //ssid wifi
char pass[] = "Dattola100"; //password wifi
//char server[] = "";  // IP for Local Cloud Server
char server[] = "";  // URL for Blynk Cloud Server
int port = 8080;

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

float h; //dht22
float t; //dht22

BlynkTimer timer;

void lightOn();
void lightOff();

boolean LampState = 0; 
boolean SwitchReset = true;

const int PULSANTE_EXT = D8;
const int ALIM = D6;  

const int BUTTON_DIMMER = D5; 
const int LED = D1; 

//---------------setup dimmer button------------

int dir = 70; //step dimmer +e-
int lum = 0;
boolean toggle = false;


void setup()      
  pinMode(2, OUTPUT); //led board esp 
  pinMode(D2, OUTPUT);// Relay led down ON/OFF
  pinMode(ALIM, OUTPUT);
  pinMode(LED, OUTPUT);
  digitalWrite(ALIM, HIGH);
  digitalWrite(2, HIGH);   //spegni led ESP
  digitalWrite(D2, HIGH); // relay led down 0
  WiFi.begin(ssid, pass);  // Non-blocking if no WiFi available
  Blynk.config(auth, server, port);
  timer.setInterval(100L, ButtonCheck); //ciclo button on/off
  timer.setInterval(100L, dimmerled); // ciclo dimmerled
  timer.setInterval(4000L, myTimerEvent); //dht22 4sec 
  timer.setInterval(1000L, rssi); //rssi power wifi
  timer.setInterval(1000L, blinkLedWidget); //
  //Blynk.syncVirtual(V2); //sync app blynk pin V2
  Serial.println("DHT22 Blynk ready !!!");

  ReCnctCount = 0;
void loop() {;

  if (Blynk.connected()) {  // If connected run as normal;
  } 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 #");
      Blynk.connect();  // Try to reconnect to the server

//-----------------------------------------------Button ON/OFF------------------------------------------

void ButtonCheck() {
  boolean SwitchState = (digitalRead(PULSANTE_EXT));
  Blynk.virtualWrite(V2,LampState); //Aggiorna il widget blynk on/off sincronizzato con pulsante ext
   if (!SwitchState && SwitchReset == true) {
    if (LampState) {
    } else {
    SwitchReset = false;
  else if (SwitchState) {
    SwitchReset = true;
void ToggleRelay() {
  LampState = !LampState;
  if (LampState) {
  else lightOff();
void lightOn() {
    digitalWrite(ALIM, LOW);
    LampState = 1;   
void lightOff() {
    digitalWrite(ALIM, HIGH);
    LampState = 0;

//---------------------------------------DIMMER LED BUTTON-------------------------------------

void dimmerled() {
   if (digitalRead(BUTTON_DIMMER) == HIGH) {
    toggle = true;
    lum += dir;
    if ((lum >= 0) && (lum < 840))
      analogWrite(LED, lum);
  } else { // toggle direction
    if (toggle) {
      dir = -1 * dir;
      toggle = false;

  int SwitchStatus = param.asInt();
    if (SwitchStatus == 2){
  else if (SwitchStatus){
  else lightOff();

void myTimerEvent() {
  Blynk.virtualWrite(V5, t);//Temp for widget blynk
  Blynk.virtualWrite(V6, h);//humidity for widget blynk
void getData() {
  h = dht.readHumidity();
  t = (dht.readTemperature());
  if (isnan(h) || isnan(t)) {
    Serial.println("Failed to read from DHT sensor!");
  Serial.print("Humidity: ");
  Serial.print(" %\t");
  Serial.print("Temperature: ");
  Serial.println(" *C ");

//-------------widget rssi wifi--------------------
void rssi() {

Blynk.virtualWrite(V1, WiFi.RSSI()); //Signal strengt wifi 


//-----------widget vitality esp connect-----------
void blinkLedWidget()
  if (led1.getValue()) {;
    //Serial.println("LED on V1: off");
  } else {
    //Serial.println("LED on V1: on");

You have tow timers that are attempting to run different functions at EXACTLY the same time and frequency (which isn’t possible with a single threaded MCU), and one ofr those also does a Blynk.virtualWrite

Doing more than 10 blynk server operations per second is asking for trouble, so you’re on the edge with just this piece of code.

I’d say that using interrupts is your best approach rather than constantly polling physical switches.


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Thank you very much @PeteKnight ;
can you direct me where to find documentation to make the change of the code ?
I am not a programmer, but with some documentation maybe I can fix the problem.

I’ll start searching!

That’s the best strategy. There are plenty of discussions about interrupts on this forum, and plenty more on the interweb.

In the meantime, try increasing the timer intervals and make the dimmer interval longer than the on/off switch (as it doesn’t need to be as responsive).



The first approach I’ll try is to change the timer times; I’ll see how it goes… in the meantime I’ll study how to apply a different code.

I add the hw scheme for completeness

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