Intruder alert notification blynk 2.0

[PeteKnight]

@xanotic

void loop() {
  BlynkEdgent.run();
  ultrasonic();

  
}

You are calling your ultrasonic() function in your void loop, and that function contains this line of code:

@xanotic

Blynk.virtualWrite(V0, distance);

This is the same as putting that Blynk.virtualWrite() command directly into your void loop, and this breaks the golden rule of Blynk - no Blynk.virtualWrite() commands in the void loop.

I’ve already pointed you to the documentation which explains why this is a really bad idea in your previous topic…

@PeteKnight

First of all, DO NOT RUN THIS CODE! it will flood the Blynk server with far too many Blynk.virtualWrites per second.

Start by reading this:

https://docs.blynk.io/en/legacy-platform/legacy-articles/keep-your-void-loop-clean

so, once again, DO NOT RUN THIS CODE! it will flood the Blynk server with far too many Blynk.virtualWrites per second.

You need to call your your ultrasonic() function with a BlynkTimer, not from the void loop.

You will also need to use a “Flag” variable so that you only send one notification each time the level falls below 5cm, otherwise you will quickly run out of notifications as they are limited to 100 per 24 hour period. You should read this for more information…

Events, Notifications and the use of "Flag" variables

Update 19th May 2022 - you’ll see references to a limit of one event per minute in this tutorial. It appears that this limit has now been removed. I’ve not yet tested this myself, and when I do I’ll update the tutorial to reflect my findings. I’m seeing quite a few posts from people who are finding it difficult to get notifications working in Blynk IoT, and who don’t understand how to use “flag” variables to limit the number of notifications that are sent for any given alert situation. I thoug…

Pete.