I got a HC-06 bluetooth module for wirelessly connecting to my PixHawk flight controller. As it is dangerous to use an unprotected board within my copter I designed a litte housing for it.
The opening for the connector pins is asymmetric with more space in one direcrtion. This is intended for keying the connector .
Finally I used two BEC 2 pin connectors which are glued together using CA to get a 4 pin connector. They are asymetric, so they will utilise the keying and fully plug-in only in one direction.
From one photo you can see my latest cable harness for connecting both Micro Minim OSD and HC-06 in parallel to my Pixhawk Mini Telem port. To not overload the Pixhawk power supply I added an additional 5V power cable which goes directly to the UBEC.
You will find the Micro Minim OSD housing at https://www.thingiverse.com/thing:3861556. Meanwhile I am using two servo connectors there which are glued together same way.
I found out there that are two versions of HC-06 which differ in size. The fist one has a board length of about 36mm, for which my original housing will match. The other one has a board length of about 39mm and is also a bit more wide, for which the second housing design will match.
Print in orientation as shown to avoid supports. After printing just insert the module and blue the lid with some drops of CA to the housing. Remove the brim of the lid after glueing.
If using transparent filament you can still see the LED and read the pin description on the board.