I'm having problems in communication between arduino and my app

I saw now that you added an Arduino code :flushed:
Just please be aware that when you senddata to the app, only the last sending of a message shall be ended with a println(),
In other words: each println() terminates one message so, if within a message you want to transmit more values, you can do it, and only the last value shall be transmitted via a println(). In this case, to separate each value transmitted within a single message you can compose a message by separating the values with a separation character, for example a ';' or a '|'. The app, once received the complete message (terminated by the println(), )shall parse the message looking for the separators (';' or '|') and split the values in one list.
something like:

The encryption requires that every time a communication is established, a BT pin is supplied, this is really annoying 'tll the development is in progress. Typically I leave it not set.

EDIT (twice) the image was wrong, now it's correct

Okay. Will get back with the results. Hopefully🤞two-way communication will work now.

:crossed_fingers: Well !!!

Clearing those two global variables after the procedure call is unnecessary, and makes it harder to inspect the variable contents later with Do It.

but this is because I've condensed everything in the clock event.
If the complete app will become "big" it's better to have the input buffer cleaned (after it has been used) and the same for the list. Otherwise, due to some possible asynchronicity (I don't even trust in Operating Systems exact timings :grimacing:) the parser procedure could (Murphy's law) work on a old buffer...