The jetibox profi can display in real time 4 telemetry values. I was thinking it would be great to have some value send by the ardupilot mega 2. I spend some time to understand the new jeti EX protocol (now public by jeti: http://jetimodel.cz/data_downloads/117/jeti_telem_protokol-ex_cz.pdf) and patch arducopter 2.6. code to be able to report some data: gps, altitude, power, compass.
I connect the ardupilot mega board to the jeti rsat using UART2:
The most useful telemetry value is the voltage of the battery, with an alarm when it goes below a value.
I also like the height to know how height is the copter. An alarm is also send when motor are armed (I am waiting from jeti to have the possibility to make my own alarm sound). Theoretically all value computed by arducopter software can be reported. I also use the old jeti protocol to be able to set different pid value from the jeti box.
A small video showing the telemetry in action:
The code (not very clean) is here: http://code.google.com/p/arduino-jeti-communication/
A previous project: http://www.diydrones.com/profiles/blog/show?id=705844%3ABlogPost%3A219277