Push a button on device light a LED on the Project DashBoard

Need Help With My Project
1

Hi,

I’m trying to do a very simple thing.

I have one switch on my device and one LED on my Dashboard.

I would like to detect a switch change in state and do a single virtual write to the virtual pin to change the state of the LED on the dashboard?

I’d rather not use a timer, this works, but consumes needless bandwidth for a simple switch, and builds in a latency.

This is my attempt at doing this but it causes a flood error pretty fast.

define BUTTON1 V2 \virtual pin 2 with LED on dashboard

define BUTTON1_P 4 \switch connected to hardware pin 4

int B1V;

void loop()
{

Blynk.run();

B1V=digitalRead(BUTTON1_P);
if(B1V!=BUTTON1) Blynk.virtualWrite(BUTTON1,digitalRead(BUTTON1_P));
}

2

I’m not sure on which platform you are developing, but in case of Arduino, have you seen the LED widget example? You need to define said widget in your code.

3

You have logical error here. Should be something like that

  int prev = -1;
  int B1V;

  void loop() {
      Blynk.run();
 
      B1V = digitalRead(BUTTON1_P);
      if (B1V != prev) {
          if (B1V) {
                Blynk.virtualWrite(V2, 255);
          } else {
                Blynk.virtualWrite(V2, 0);
          }
      }
      prev = B1V;
 }
4

Thanks,

That seems to have fixed the issue. I guess I’ve been having an issue understanding that the virtual pins are an address and do not have a value.

Regards,
David