NodeMCU + Blynk + OTA disconnect all!

Hi everyone!
I have a system with NodeMCU controlled by Blynk.
My code works correctly, but if I try to add code for OTA, my system disconnect and reconnect from wifi every 5/10 sec!
My system sends to Blynk data from my solar panel by INA219.
My system is not really close from router wifi, but without OTA code works correctly.
I have another NodeMCU to test, and instead of making the method that send solar panel data, I use a test method that send sum of number. If I stay near my router wifi, my test system works correctly and I can load new code by OTA. But If I walk away and I approach the area where I have the solar panel, NodeMcu disconnect and riconnect and I can’t load new code by OTA.
Why all this???
my code is this, thank you

#include <Blynk.h>
#include <ESP8266mDNS.h>
#include <WiFiUdp.h>
#include <ArduinoOTA.h>

#include <Wire.h>
#include <Adafruit_INA219.h>
#define BLYNK_PRINT Serial

#include <ESP8266WiFi.h>
#include <BlynkSimpleEsp8266.h>

char auth[] = "******";
//char auth[] = "*****";  //  TOKEN DI PROVA

Adafruit_INA219 ina219;

char ssid[] = "ERRICIOFFI2.4";
char pass[] = "lunasissy";

//char ssid[] = "Linkem_0EC983";
//char pass[] = "bjig3vug";

//char ssid[] = "FERRIDEA";
//char pass[] = "possochiedere?";

float shuntvoltage = 0;
float busvoltage = 0;
float current_mA = 0;
float loadvoltage = 0;
float power_mW = 0;
float energy = 0;
float current_h = 0;
float current_day = 0;

unsigned long previousMillis = 0;
unsigned long interval = 100;
unsigned long currentMillis = 0;

#define relayFaretto10WD4 D4  
#define relayMadonnaD5 D5 
#define greenLEDD7 D7    
#define redLEDD8 D8 

#define buttonFaretto10W V0  // >> su D4
#define buttonMadonna V1     // >> su D5
#define timerFaretto V2      
#define timerMadonna V3      
#define correnteIstantanea V4
#define potenzaIstantanea V5
#define energiaTotale V6
#define correnteTotale V7
#define correnteTotaleDay V8
#define correnteTotaleDayGraph V9

boolean isFirstConnect = true;
boolean isConnesso;
boolean canSendCurrentDay = false;

BlynkTimer timer;

void setup(void) {

  Blynk.begin(auth, ssid, pass);
 // Blynk.config(auth);
  //Blynk.connectWiFi(ssid, pass);
  ArduinoOTA.begin();  // For OTA


  pinMode(greenLEDD7, OUTPUT);
  pinMode(redLEDD8, OUTPUT);
  pinMode(relayFaretto10WD4, OUTPUT);
  pinMode(relayMadonnaD5, OUTPUT);

  digitalWrite(relayFaretto10WD4, LOW);
  digitalWrite(relayMadonnaD5, LOW);

  // Setup a function to be called every second
  timer.setInterval(1000L, letturaPannelloProva);   //// TEST METHOD
  timer.setInterval(1500L, sendInaValues);  
  timer.setInterval(3000L, controllaConnessione); 

void loop(void){; // Initiates BlynkTimer

void letturaPannello() {

    shuntvoltage = ina219.getShuntVoltage_mV();
    busvoltage = ina219.getBusVoltage_V();
    current_mA = (abs(ina219.getCurrent_mA())/1000);
    power_mW = ina219.getPower_mW()/1000;
    loadvoltage = busvoltage + (shuntvoltage / 1000);
    current_h = (current_h + current_mA / 3600)/1000;   // conteggio corrente totale
    current_day = (current_day + current_mA / 3600)/1000;   // conteggio corrente giornaliero
    energy = (energy + loadvoltage * current_mA / 3600)/1000;  // conteggio corrente energia 

void controllaConnessione(){


    digitalWrite(greenLEDD7, HIGH);
    digitalWrite(redLEDD8, LOW); 
    isConnesso = true;
    digitalWrite(greenLEDD7, LOW);
    digitalWrite(redLEDD8, HIGH);   
    isConnesso = false;
    //Blynk.begin(auth, ssid, pass);

void sendInaValues(){
  Blynk.virtualWrite(correnteIstantanea, current_mA);  // V4  
  Blynk.virtualWrite(potenzaIstantanea, power_mW);   // V5  
  Blynk.virtualWrite(energiaTotale, energy);  // V6   
  Blynk.virtualWrite(correnteTotale, current_h);   // V7   
  Blynk.virtualWrite(correnteTotaleDay, current_day);  // V8  
  if(canSendCurrentDay){ // ALLO STOP DEL TIMER FARETTO
    Blynk.virtualWrite(correnteTotaleDayGraph, current_day);  // MANDO IL VALORE TOTALE DELLA CORRENTE PRODOTTA
    current_day = 0;
    canSendCurrentDay = false;

BLYNK_WRITE(buttonFaretto10W){  //controllo VIRTUAL Button Faretto   V0  >> D4
    digitalWrite(relayFaretto10WD4, HIGH);  // START RELAY FARETTO
    digitalWrite(relayFaretto10WD4, LOW);   // STOP RELAY FARETTO
    canSendCurrentDay = true;

BLYNK_WRITE(buttonMadonna){  //controllo VIRTUAL Button Madonna    V1  >> D5
    digitalWrite(relayMadonnaD5, HIGH);  // START RELAY MADONNA
    digitalWrite(relayMadonnaD5, LOW);   // STOP RELAY MADONNA

BLYNK_WRITE(timerFaretto){  // timer V2 >>> buttonFaretto V0
  if (param.asInt() == 1) {
    Blynk.virtualWrite(buttonFaretto10W, 1); // button set to ON from timer
    //digitalWrite(relayFaretto10WD4, HIGH); 
    Blynk.virtualWrite(buttonFaretto10W, 0); // button set to OFF from timer
    //digitalWrite(relayFaretto10WD4, LOW); 

BLYNK_WRITE(timerMadonna){  // timer V3 >>> buttonFaretto V1
  if (param.asInt() == 1) {
    Blynk.virtualWrite(buttonMadonna, 1); // button set to ON from timer
    //digitalWrite(relayMadonnaD5, HIGH); 
    Blynk.virtualWrite(buttonMadonna, 0); // button set to OFF from timer
    //digitalWrite(relayMadonnaD5, LOW);

//////////////////     S Y N C  ///////////////////////////////////
  if (isFirstConnect) {
    Blynk.syncVirtual(energiaTotale);     // V6
    Blynk.syncVirtual(correnteTotale);    // V7
    Blynk.syncVirtual(correnteTotaleDay); // V8
    isFirstConnect = false;
  isConnesso = true;

  energy = param[0].asFloat();

  current_h = param[0].asFloat();

  current_day = param[0].asFloat();

void stampaValori(){
  Serial.print("Bus Voltage:   "); Serial.print(busvoltage); Serial.println(" V");
  Serial.print("Shunt Voltage: "); Serial.print(shuntvoltage); Serial.println(" mV");
  Serial.print("Load Voltage:  "); Serial.print(loadvoltage); Serial.println(" V");
  Serial.print("Current:       "); Serial.print(current_mA); Serial.println(" mA");
  Serial.print("Power:         "); Serial.print(power_mW); Serial.println(" mW");
  Serial.print("Energia:         "); Serial.print(energy); Serial.println(" mWh");

void letturaPannelloProva() {
      shuntvoltage = ina219.getShuntVoltage_mV();
      busvoltage = ina219.getBusVoltage_V();
      current_mA = current_mA+0.5;
      power_mW = power_mW+0.5;
      loadvoltage = busvoltage + (shuntvoltage / 1000)+0.5;
      current_h = current_h+0.5;   // conteggio corrente totale
      current_day = current_day + 0.5;   // conteggio corrente giornaliero
      energy = energy + 0.5;  // conteggio corrente energia

What happens if you change your timers so that they don’t overlap every 3 seconds?
Maybe even try disabling the timers one at a time to see if there’s an issue with one of the functions that they are running.

I’d also add a function to send RSSI, and uptime to Blynk so that you have a better concept of your NodeMCU’s signal strength and whether you’re also seeing reboots.


Thank you Pete.
Why should the signal strength change if I only added the OTA?I’ll try to add RSSI, what are the acceptable values ​​of db??
Analyzing my code, the set of OTA is right?
Thank you!

I read, value between -20 and-50db right?

I believe that -30db is the best possible result, if you’re getting worse than -85 then you’re likely to be on the edge. Bad weather and other atmospheric conditions make the readings worse, so monitor the results and maybe plot them on a Superchart.

I’m not saying it would. However, you’re describing a situation where distance from the router affects how the device performs, so you need some metrics to allow you to understand what’s happening better.

The OTA section of my void setup looks like this:

ArduinoOTA.onError([](ota_error_t error) { ESP.restart(); });
ArduinoOTA.setHostname(“device hostname in here”);


Ok I’ll let you know.
Thank ypou

I just measure RSSI with another MCU. In the same place of NodeMCU/Solar I misure values between -77 and -81.

-81 dBm is a very very poor connection

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I agree, but if it’s consistent that you’ll usually be okay most of the time. I’m getting these numbers at the moment from a few of my devices and they’re still useable…

Having said that, I’m not running Blynk code on these devices, just MQTT, so there’s less overhead.

I think @Andrea_Errico needs to improve the Wi-Fi numbers, either with a Wi-Fi booster or maybe switching to something like a Wemos D1 Mini Pro with external antenna.


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Pete, are you using your IPcams with Blynk App ?

No, these are Sonoff S20’s that cameras and a mini PC are plugged into, so that I can remotely reboot them if needed.
I have successfully displayed the video from the cameras in the Blynk app, but to be honest the dedicated app for the cameras (Reolink) is by far the best way to view the footage. My neighbour and I both have the same type of cameras so we share the camera credentials so that we can view each other’s cameras in the app and that works really well.


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Thank you for reply.
The point is to understand if Arduino OTA creates a strong impact on the connection. There are no references on the web to understand this impact?
I will try anyway to bring the modem closer to the location.
I also have an ESP32 available, could this be improved?
Let me know
Than you

The best way to understand this is by experimentation.


Ok, I’ll let you know
Thank you

ArduinoOTA.onError([](ota_error_t error) { ESP.restart(); });

I think here is the problem.

That’s a standard OTA error handling routine. It’s exactly what I use in all of my sketches.
It only kicks-in if an OTA update fails for some reason, so doesn’t have any effect on normal day-to-day operation of the device.


Thanks for your reply.
So, I move my router more less 5 metri from last position. Consider that my router is on the upper floor and the nodemcu on the ground floor (in my garden).
Finally I can use OTA system!! I’m so happy!
The only strange thing is that, through RSSA, I don’t read high values, more less -80dB!
However, for now it seems to work. If I have any problems I will let you know. Thanks
To your knowledge, in my code for OTA I add only ArduinoOTA.begin() in setup and ArduinoOTA.handle() in the loop
So, we can say that connection influence OTA?

Your original question was about why having OTA in your sketch was causing problems. The problems have now gone away, after moving your router, but your RSSI values have not improved.

I’d say that the findings are inconclusive. I run OTA on the devices in my screenshot earlier, and don’t have problems.

If it’s possible for you to add a Wi-Fi repeater (preferably a wireless access point that’s connected to your router via an Ethernet cable) then you’ll probably see less issues overall anyway, and you’ll get netter internet access in the garden as a spin-off.

I recently bought one of these:

that I’ll be fitting in the next few weeks to try to improve my outdoor reception a bit.


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Ok thank you.
After installation of NodemCU on my solar system I can upload new code by OTA.
If I restart my pc and my Arduino IDE I dont’ see IP port to upload new skecth why?
Thank you

I have this issue quite often on my system, not exactly sure why, but @Blynk_Coeur pointed me in the direction of Bonjour Browser…

Install Bonjour Browser and whenever you have problems with the OTA ports not being shown in the IDE just fire it up and check the IDE again. The OTA ports will have magically appeared again.


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