iPhone camera/GoPro mount interface

This project will allow you to use your iPhone as a helmet camera using the GoPro helmet mount as a mounting system.
Here is a link to the youtube video: http://www.youtube.com/watch?v=leJv4hBYe80&feature=channel
If you don’t already have a GoPro mount on your helmet, you can get one, and everything you’ll need for this project, (apart from a few easily obtainable “found” parts) in the so-called, “Grab Bag of Mounts” available from Amazon.com for about $17.00, or from any GoPro dealer.
GoPro makes a very efficient sport camera, but there may be times when you will be glad of an auxiliary camera option for your helmet: such as, those times when you may be low on battery, or out of memory.
Or you may want a redundant back-up for the shoot, with another camera recording option, or, you may simply have forgotten to bring your GoPro along.
Chances are, you WILL have your iPhone along with you on most of these occasions, however, so pack this easy mount project along with your regular sports gear, or in the glove box of your car, and you’ll always be ready to film.
Necessary parts from the Grab Bag include the curved-surface, adhesive helmet mount, which may already be attached to your helmet. You’ll also need a quick release buckle, a Thumb Knob with nut and bolt, an extender called a “Pivot Arm Assembly” and a couple of metric M5 bolts and acorn nuts.
I cut an angled piece of thin steel from a computer component, (this CD drive) sized 3 X 2.5 inches, with a 5/8” lip and then used contact cement to cover the inside surface with thin plastic cut from a DVD case which will later allow me to countersink my mounting bolts.
The plastic can be cut with any razor knife, but I used a Dremel style tool to cut out the steel. It was pretty easy, to get a fairly straight edge with such a small piece. Then I used some steel wool, to polish the outside face, in a kind of swirly pattern, just for looks.
The pivot arm is going to be used at right angles to the way it is normally used for GoPro applications. I drilled a hole through the metal to attach the M5 bolt to a GoPro acorn nut.You’ll have to cut, file, or Dremel a few mm off the length to get it to fit. The thread length should be about 8mm.
Here’s the fiddly bit. The arm may swivel with only one attachment point, so I wanted two. What I did, was to fill the gaps on both sides with J-B Weld, and waited till it dried rock solid.Then I drilled another hole through the arm and the steel stand, and added another M5 bolt and an acorn lock nut from Home Depot. The thread length was about 12mm. I used a small washer here too, again, just for looks.
I used a ½” drill bit to countersink the bolts, so I have a perfectly flat back plate.
I used a hard shell iPhone case and hook-sided Velcro to attach the phone.
3M Velcro is super strong, but I secured the Loop-side to the mount with 1/8” rivets, so it wont’ ever peel up. The snaps also give the project a cool industrial look.
You can get a handful of snap fasteners and a setting tool, for a couple of bucks, or ask a shoe repair person to do the job for you.
You can either use an inexpensive iPhone case and permanently attach it to the mount, I used rivets for this example.
If you don’t have a Dremel, or just want a simplified, but still functional version, I made a prototype out of a VHS tape case. I added two extra layers of VHS case plastic to fortify the basic angled shape, and a single drill hole mount.
The arm assembly is stabilized by a couple of bits of plastic, contact cemented to the mount plastic, to help hold it in place.
This mount variation is neither as robust, nor as interesting looking as the steel version, but will do in a pinch for low-intensity sporting applications.
I wouldn’t use either mount for crash worthy sports like mountain biking, without some thought to reinforcing the mounts, or else having an expectation that the iPhone probably wont survive a crash regardless.
If you decide to go the Velcro route, it is advisable to fix the snaps through the Velcro to the mount, as even the best contact Cement won’t reliably hold the
Velcro to the polyurethane indefinitely. This type of plastic is notoriously hard to pretty much all types of glue. It laughs at Gorilla glue, 5-minute epoxy, J-B Weld… just about everything.Contact cement works okay, but not for a permanent bond subject to repeated pulling. I use BARGE All purpose cement, available from Shoe Makers supply stores.

This mount, is designed to hold my iPhone on an extendable monopod. The monopod I use has a standard quick release plate such as is found on many tripods.
Unfortunately, these plates seem to be all slightly different and not interchangeable.

Adapter mounts can be easily created out of plastic cut from VHS tapes, cemented together with contact cement like a little step pyramid of a size identical to the original mount, and filed, sanded, or ground into an angled sided block to fit. Go here for detailed instruction on tripod quick-release plate, GoPro interface. 
I made custom mounts for both my monopod and my tripod, to quickly transition from Gopro, to DVcam, to iPhone, with minimum hassle.