GoPro Hero3 + Black - DIY external mic adapter cable to fit inside case (waterproof)

I very soon realized the gopro is a superb camera also for the family shots. The sound quality is ok without the case, usable with the skeleton door and really poor with the standard door. The problem with the skeleton door is not providing the protection I need from sand, water, mud, dust etc. This is where the need of a sealed case comes in and the only solution is an external microphone. I do not intend to submerge this mod in water. I basically want to make sure that an accident will not destroy the camera.

The hero3 + protective case does not leave more than 1.8 mm for the connector and cables between the camera and the case. Modifying a power cable is relatively easy as only one of the pin rows are used in the USB-connector. You may for example easily attach a "foil" cable to a modified USB-connector. Modifying a USB to 3.5mm mic adapter cable however involves both rows in the 10 pin USB connector making it a little more tricky (even if only 5 pins are used in total). I added this video to show it is possible for anyone with basic skills and good patience. It takes a couple of hours but is absolutetly worth it.

Your need:
A cheap GoPro mic adapter (miniinthebox.com)
Hot glue, expoxy glue and Sikaflex/silicone
Basic soldering tools but a thin soldering tip
Metal file and/or dremel
Small knife
Magnifying glass
33kOhm resistor unless you reuse the one that is soldered to the PCB in the connector, but this requires a microscope. I used one slightly bigger.

The only tricky part of this mod is that the USB-connector requires alot of care when stripped down or all the pins will loosen = the connector is destroyed. Buy one extra cable as backup. Take it really slowly and you will succeed at least in your second try :) Here is how to modify the USB-connector.
Remove the USB-connector plastic case
Solder off the cables and the resistor from the PCB (or buy a slightly larger size (not value) resistor)
Remove the metal chassi of the USB-connector and file it to required length (It should completely "dissapear" into the USB connector of the gopro)
Using a metal file or dremel and a sharp small knife carefully start removing the plastic of the connector until the correct lenght has been achieved, do not damage the really thin pins. Glue with epoxy from time to time to avoid the pins from loosen. Keep the PCB until this stage for stabilization.
Now cut away the PCB and save 0,5 mm in lenght of the pins so you have good soldering points.
Solder back the cables and the 33kOhm resistor to the connector.
Make sure the pins inside the connector has not moved from its positions and glue with epoxy.
. Apply hot glue to get something to hold on to when disconnecting from the camera.
drilling and getting thorugh the door is not explained here but the plastic takes any abuse (step drill, wooden drill, HSS drill at any speeds), no risk for cracks.

PS
When using a passive external microphone like this you cannot record video and at the same time use the gopro app. The wifi causes annoying sound interference. You may however use the wifi remote without problem. I read in a forum that when using a microphone with internal battery power this problem is not present, I havent confirmed.