Here are a couple of images that show a hacked 2.5mm 4-pole AV plug cut down to its smallest possible form.
I converted this to 3-pole by omitting the tip. For mkII I will keep the tip for mechanical reasons, GoPro puts out only one channel of audio for live view, so we just need the first 3 poles to have conductors attached.
The motive was to be able to have live video out while using the waterproof case, and it works! I bring the wires through the back of the case, where they are sealed and a servo lead terminates on the outside. This position is a neutral point for the tilt and roll arcs, a great place to make a connection!
Comments
http://diydrones.com/profiles/blogs/low-profile-2-5mm-av-plug
Here's the rest of the process.
Eric, I've made a couple of these now and mostly just forget the audio as it definitely makes the project more difficult. Try soldering the video(white) first then feed the audio(red) through. It's easiest if you pull the servo cable apart so you have three separate wires, then you don't have to worry about everything coming out the same length when you put all the parts back together.
Did you see the second blog post I did that shows the rest of the steps, I meant to add it to this one but accidentally made it a separate post.
I'll try to get a video together at some point, no problem.
I like this. It inspired me to *try* and make my own. I get what needs to be done up until soldering the white wire. The white wire soldering step seems difficult to solder without damaging the red wire. Any tips for the white wire? Also, on my connector, the black sleeve on the second connector from the right was quite snug and require a bit of force to remove. If ever you make another one, a video would be nice. Thanks for sharing this.
We need to measure the clearance available between the camera and case. I used feeler gauges, but clay worked as well, you can see it in the caliper jaws.
About 1mm is all we get, the sides do taper out so the clearance gets better towards the back of the camera, plenty of room for 32 gauge servo wires.
Cut the plug down leaving a ~1mm of shoulder. You want a nice clean finish so that when you seperate the pieces everything will come apart without damaging the insulation layers.
It's a good idea to test fit the shoulder piece and make sure it will fit in the case without interference.
Perfect, .06mm to spare! Damn, there isn't much room in these cases. I'm curious to see how the Hero3 is set up.
Next, we need to figure out how to stagger the lengths of the inner pieces so our conductors can be soldered to the inner part of the poles and still leave room to get everything back together.
This is the basic idea.
I'm using red for audio, it can connect to either the tip or the second from the tip. GoPro has only a mono mic, it puts signal out on two poles of the connector, but we only need one since most of our video Txs only have one channel of audio anyway. White will be video, this connects to the third pole from the tip. Black is ground, it is soldered to shoulder of the plug.
Construction method for low profile 2.5mm 4 pole
Here is the starting point (my auto white balance was having trouble, it gets better)
great idea thanks for sharing this should go well with the water proof aquacopters .....
Thanks for the reply! Definitely get some more pics during the build... I'd like to try this. Just bought a $12 plug-irc/vtx but this would be lighter and I'd have the $12 one as a backup.
I'm going to make another one, I'll snap some pics of the process :)