I played around with a telemetry system a while back. I had an LCD display, but I was never satisfied with it. I think audio (voice) data is a much more effective means of getting information to the RC pilot.
After seeing a system from a German sailplane company last year at Toledo (http://www.picolario-usa.com/) I dusted off my telemetry project and attached the output to the guts from an FRS walkie-talkie via a voice synthesizer. Now when I hit the spring-loaded button on my transmitter I hear a voice say "Eighteen hundred fifty-six RPM" (or whatever the current reading is.
I built this for a little over a hundred bucks and have it interfaced to my GV1 governor. This winter is dragging on so I am probably going to add the temperature and voltage routines back into it.
