Alerting about fire from arduino to phone app

Hi im struggling with my project for school.

I found great tutorial about communication between arduino and phone app here:

but there is one problem.
These messages are sent by click. How to make it so that the app itself scans if the sensor has detected a fire and that this message is sent as a notification/alert to phone.

char Option = 0;
Option =;

Flame_Sensor_Reading = analogRead(Analog_Flame_Sensor_Pin);

Option = "F";
Serial.println("Flame detected");
Option = "C";

I tried also this tutorial, but unfortunetly I ended up with displaying every serial line printed in monitor, not only this one placed in if statement.

Any hints? Thanks.

Well I forgot to mention I know how to do this for 1 variable but I have no idea how for 2 variables, for 1 I simply read serial monitor and the biggest problem with it is that any information coming thrue serial monitor is saved in this variable in app. I want to specify which variable is saved from concrete variable or if statement in arduino.

It sends all the variables every time one of them changes, that is, it always sends: sensor1 + "," + sensor2 + "," + sensor3

The app will receive, for example: