I wanted to use my BF-F8 as a fox for a ham radio fox hunt. This mount slides onto the battery and holds an Arduino nano. The lower part of the mount holds power wires for the Arduino. The charge contacts on the battery have the full battery voltage on them all the time, so I made some springy fingers to contact the charge terminals.
Also included is a mount for a ublox neo 6M GPS. I'm going to use this backpack for APRS too.
All screws are 4-40 1/4" or 3/8"
I drew this all up in DesignSpark Mechanical. The .rsdocs are included.