The mini OSD has always been the number one solution an open source OSD ( cheap + arduino + MAX7456 ) but it lacked few pinout.
Here is the the 1.1 with everything you need. This OSD has different firmeware that makes it the only OSD to be able to display telemetry data for all of these plateforms :
- Arducopter ( APM )
- OpenPilot CopterControl CC3D
- Multi Wii
- Naze 32 ( great tutoria about it available on OscarLiang.net)
Good to know : When flashing the fonts, you need to also power the 12v side of the board.