fresh start with MDBT42Q , some specs before start toe code

Hi - sorry for the delay, I was away last week...

so the PI is the client and the MDBT42Q will be the server , right ?

Usually, yes. Although the opposite is possible.

what is the approximately~ distance I can use for communication ?

Realistically around 10M

can I connect an external antenna to the MDBT42Q and see if it's make any changes?

Not easily on the normal board, but we do sell some where this is possible: https://shop.espruino.com/mdbt42q/mdbt42­q-breakout-ufl

I have a working code on Arduino BLE( my problem with the Arduino is the distance , I get around ~ 4 meters only ), can I publish the code here and get some help converting it to java?

Yes, that's fine.

what do I need to do in order to see "live" data (timestamp - just to see it's alive), or even the latest byte I sent to the device?

NRF.setServices only sets the value of data at that point. To update the value that is available you need to keep calling updateServices when the data changes. There is an example at http://www.espruino.com/Reference#l_NRF_­updateServices

is there any to see console.print while I'm connecting using web ide on my computer?

If you're connected to the same computer you can sometimes use the IDE and python code at the same time (but not different computers).

Otherwise yes, you'd have to use a serial cable.

when I use a python code to send data I get this error: Characteristic 3e440002-f5bb-357d-719d-179272e4d4d9 does not support write operations!

Can you write to it using an app like NRF Connect on your phone? it would help to rule out any issue with the Pi.

Hope that helps!