Blynk App issue

Hello guys,i am new in this field of projects and i have an issue with my arduino project. I am using the Wemos D1 mini pro with the ESP8266 and i want to send data via wifi on Blynk app . The code is fine(i mean do error messages) but it seems that the arduino doesn’t connect to the app . Any ideas?

thank you!

You’re going to need to post the code first…

What does your serial monitor show?


Note : i’ve erased some data such as auth,network ssid and password for security reasons.

[Unformatted code removed by moderator]

it pops up but it’s empty, should it have anything written?

@Nikolas_Chrysostomou please edit your post, using the pencil icon at the bottom, and remove the blockquotes from your code and put triple backticks at the beginning and end of each sketch so that it displays correctly.
Triple backticks look like this:

Copy and paste them if necessary.

If you’ve set the serial monitor to the correct baud rate then you should see messages from the Blynk library.

Exactly what connections do you have to your Wemos?


i have the pins from the bme280 sensor

So you have some pins from the sensor connected to unknown pins on the Wemos?
And your code?
And your serial monitor output?

If you want us to help you then you have provide useful information.


Wemos -> BME 280

3.3 V - -> Vin


D1 --> SCL

D2 --> SDA


#define BLYNK_PRINT Serial    
#include < ESP8266WiFi.h>
#include  <BlynkSimpleEsp8266.h ></p><p>
#include "Seeed_BME280.h"
#include < Wire.h>
BME280 bme280

char auth[] = "";
char ssid[] = "";
char pass[] = "";

void setup()
  Blynk.begin(auth, ssid, pass);
  Serial.println("Device error!");

void loop()
  float temp = bme280.getTemperature();
  Serial.print("Temp: ");
  Blynk.virtualWrite(0, temp); 
  Blynk.virtualWrite(4, temp); 
  float pressure = bme280.getPressure(); 
  float p = pressure/100.0 ; 
  Serial.print("Pressure: ");
  Blynk.virtualWrite(1, p); 
  float altitude = bme280.calcAltitude(pressure);
  Serial.print("Altitude: ");
  Blynk.virtualWrite(2, altitude); 
  float humidity = bme280.getHumidity();
  Serial.print("Humidity: ");

  Blynk.virtualWrite(3, humidity); 
  ESP.deepSleep(5 * 60 * 1000000); 



1 Like

I don’t know what happened but somehow i got data on the app!

First of all, when you post code on the forum it’s one set of triple backticks at the beginning and and one at the end. DO NOT put more sets of triple backticks throughout your code as this splits it up into smaller code sections which make it impossible to copy/paste as one sketch for debugging purposes.
I’ve fixed the formatting this time, but in future incorrectly posted code will be deleted again.

The serial monitor output really needs to be the part when the device boots/awakes as this will show the Blynk connection attempts and useful debug data. As I said earlier, serial monitor output really needs to be copied and pasted between triple backticks rather than posting screenshots.
Clicking the ‘Show timestamp’ checkbox in the serial monitor would also be useful, as it’s impossible to tell from the screenshot if the device is actually going into deep sleep or not.

As you’ve not mentioned any connection between GPIO16 and the RST pin and there is no Blynk connection attempts showing between temperature readings then I assume that the device isn’t actually going into deep sleep mode at all.

My advice, based on the limited information is…

  1. add a delay(1000); after the deep sleep command to allow the deep sleep to begin
  2. add a command immediately before the deep sleep command, possibly with a short delay after it, to ensure that the Blynk.virtualWrite commands are processed before the device sleeps.
  3. ensure that you have a connection between GPIO16 (Pin D0) and GND to allow the device to wake after sleeping
  4. remove the second Serial.begin(9600); command from your void setup, and change the first one to a baud rate of 74880 so that you see the D1 Mini’s system messages in a useable format when the device boots/wakes.