I also saved money.
Very easy and inexpensive and customizable to whatever backpack you use.
Video of the finished product in use can be found here:
Step 1: Materials
3/4" wide Velcro
Small machine screws, washers and nuts
1/4"-20 short machine screw
GoPro tripod mount
Step 2: Mounting Plate
It's available at Home Depot and pretty inexpensive ($4 for a 10" x 8" piece).
I used a piece about 4 1/2" x 3 1/2"
Cut the top two corners off on an angle to suit the strap locations.
Mark 4 slots in the 4 corners where the 3/4" Velcro straps will attach,
Angle the top slots to match the cut corners.
Drill a small hole at the end of each marked slot and cut between the drilled holes with a coping saw to complete the slots
Drill a 1/4" hole in the center for the 1/4"-20 thread tripod camera mount screw.
Drill a hole between the bottom slots to suit one of the small machine screws. Locate the hole close to one slot
Step 3: Straps
Use a washer against the Velcro and one against the Lexan.
Run a length of Velcro through each of the upper slots, double back over a short distance and make a hole for a machine screw. use a washer at each side of the Velcro.
Step 4: Attach to Camelbak
The lower straps are then looped around the lower portion of the Camelbak should straps
I am able to remove the Velcro straps from one side and still keep the camera/mount secured to the Camelbak.
This was a very easy, quick and cheap project.
The exact placement and length of the straps will depend on the type of hydration pack you use and the type of shoulder straps it has.
Step 5: Modifications
First, the camera angle was not adjustable with the camera in the standard right-side-up configuration and it was pointing down more than I wanted. This because you are leaning over when riding. I think the first hole and upright camera position would work for walking or other more upright activities.
Therefore, I added a second 1/4" hole for the tripod mount higher than the first hole.
Now the camera can be mounted in the upside down position, using the camera setting with the image flipped.
Now the camera can be angled upward. Much better.
Second, I added some Gorilla tape (like a stronger duct tape but 1" wide) to both side of the Lexan to help give the tripod mount and the screw/washers something to grip onto. The Lexan was a little slick.