I need to stop function after X seconds

[PeteKnight]

You need to use a BlynkTimer in timeout mode within your sketch. The simplest way to do this is as a Lambda function.

Read the timeout Timers section of this tutorial…

Using BlynkTimer or SimpleTimer

Many users seem to struggle with the basic concepts of using BlynkTimer in their projects, despite the excellent discussions and tutorials that exist on this forum, so I thought I’d write a guide that will hopefully help clarify things. It’s rather long, as it attempts to explain the reasoning behind why and how we use timers, and covers some more advanced subjects, but I’ve tried to organise it in a way that helps people to find answers to specific questions… Why use a timer at all? Let’s say …

Pete.