If statement with BLYNK_READ

Solved
,
1

Hello,
i just started in blynk and im working on lighting a real led using one button widget and closing it with the other using a NodeMCU.

I know its too easy, im just a starter in blynk and so i progress until i can do advanced projects :slightly_smiling_face:.

Anyways i want to know how to use the BLYNK_READ in the if statement,

it would be nice if you answered!

Here is the code(just in case anyone needed to see it):

#define BLYNK_PRINT Serial


#include <ESP8266WiFi.h>
#include <BlynkSimpleEsp8266.h>
char auth[] = "private";
char ssid[] = "HUAWEI-E5172-6065";
char pass[] = "private";
#define LED 1
BlynkTimer timer;

void myTimerEvent()
//i want the if statement to be here
  
void setup()
{
  // Debug console
  Serial.begin(9600);

  Blynk.begin(auth, ssid, pass);
  // You can also specify server:
  //Blynk.begin(auth, ssid, pass, "blynk-cloud.com", 80);
  //Blynk.begin(auth, ssid, pass, IPAddress(192,168,1,100), 8080);
pinMode(LED,OUTPUT);
  // Setup a function to be called every second
  timer.setInterval(1000L, myTimerEvent);
}

void loop()
{
  Blynk.run();
  timer.run(); // Initiates BlynkTimer
}
2

BLYNK_READ is the wrong function to use here.

Turning a physical LED On/Off using a button widget is more easily achieved using a single button widget rather than two. This is how to do it…

Add a button widget to your app, set it to Switch mode, and attach it to Virtual Pin V10

Then add this code to your sketch…

BLYNK_WRITE(V10)
{
  if (param.asInt()) // If the button widget sent a "1" (on)
  {
      digitalWrite(LED, 1); // Turn your LED on
  }
  else
  {
      digitalWrite(LED, 0); // Turn your LED off
  }      
}

The BLYNK_WRITE(V10) callback is automatically triggered each time the value of the widget attached to V10 changes in the app.

If you want to use two widget buttons then it gets a bit more complex, so probably isn’t the best solution for a beginner.

Pete.

3

Hello pete,
thanks for the reply!
i will try and test it and i will see if you were right.

4

Hello,
it didnt work!!!
i dont know what on earth is going on but im sure its a mistake i didnt see.
Sorry Pete for all that anger but im really just going to explode of anger,
here is the new code:

#define BLYNK_PRINT Serial
#include <ESP8266WiFi.h>
#include <BlynkSimpleEsp8266.h>;
char ssid[] = "HUAWEI-E5172-6065";
char auth[] = "private";
char pass[] = "private";
#define red 0

BLYNK_WRITE(V10)
{
  if (param.asInt())
  {
    digitalWrite(red, HIGH);
   
  }
  else
  {
    digitalWrite(red,LOW);
   
    
  }

}

void setup()
{
  // Debug console
  Serial.begin(9600);
  Blynk.begin(auth, ssid, pass);
  pinMode(red, OUTPUT);

}

void loop()
{
  Blynk.run();

}

Hope you answer soon.

5

My guess would be that either your switch widget inst connected to pin V10 in the app, or its a problem with the way you’ve connected your LED.

This means that you’ve connected your LED to pin GPIO0, which is the pin labelled D3 on your NodeMCU.

image
image700Ă—590 166 KB

This isn’t a great pin to use, because if GPIO0 is pulled HIGH at startup then it will put your NodeMCU into programming mode rather than executing your sketch. See this for more info…

It may be simpler to work with the built-in Blue LED that is located near the D0 pin. This is connected to GPIO2, so change your code like this:

#define red 2

The built-in LED has inverted logic, so HIGH will turn it off, and LOW will turn it on.
Swapping the HIGHs and LOWs in your digitalWrite commands will fix this.

Pete.

6

Hello,
It worked!
thank you for your answers and contrbuition pete!

1 Like