sending current position over UDP ?

Probably, my question should sound like 'What is the interface in hal that allows to get current cooridnates?'
The thread doesn't give information, except for the one that software debouncing takes alot of resources from Arduino.
By python file you mean this one?
forum.linuxcnc.org/media/kunena/attachments/9308/udpio.txt
It seems, for my purpose I need just the tx part of it. What confuses me is getting neede data from emc2. Seemes, I need to dig hal documentation more attentively...

Yes I would say that you will only use the TX section and of coarse the pins definition section but only with your own pins defines. The HAL pins that you have to use will connect to "axis.0.joint-pos-cmd" in the hal file for instance. There are many ways to get what you want. As I said, you will have to dig in and use some imagination.

If you read the thread you will see that I mentioned that you must rename the file to correct extensions. udpio.txt becomes udpio.py etc.
I suggest that you study the HAL integrator manual to get more info.
Short form doing it for you I don't think I can help you more.

It is not that difficult once you get the just of how HAL files work.

yep!
I guess
linuxcnc.org/docs/2.5/pdf/LinuxCNC_Integrator_Manual.pdf
That' whay I was looking for! thank you!