The general idea is to replace this:
Thereby solving two problems:
- Pitifully small battery capacity
- Wobbly camera support
The battery is an Anker PowerCore 13000 Power Bank plugged into the M20’s USB port. Given that SJCAM’s 1 A·h batteries barely lasted for a typical hour of riding, the 13 A·h PowerCore will definitely outlast my legs. The four blue dots just ahead of the strap around the battery show it’s fully charged and the blue light glowing through the case around the M20 indicates it’s turned on.
The solid model has four parts:
Which, as always, incorporates improvements based on the actual hardware on the bike.
A strap-and-buckle belt harvested from a defunct water pack holds the battery into the cradle and the cradle onto the rack, with a fuzzy velcro strip stuck to the bottom to prevent sliding:
The shell around the camera is basically a box minus the camera:
The shell builds as three separate slabs, with the center section having cutouts ahead of the camera’s projections to let it slide into place:
The new shell version is 30.5 mm thick, so a 40 mm screw will stick out maybe 5 mm beyond the nylon locknut. I trust the screws will get lost in the visual noise of the bike.
A peg sticking out behind the USB jack anchors the cable in place:
The front slab and center top have curves matching the M20 case:
The camera model has a tidy presentation option:
And an ugly option to knock the protruberances out of the shell:
The square-ish post on the base fits into an angled socket in the clamp around the seat rail:
The numbers correspond to the “Look Angle” of the socket pointing the camera toward overtaking traffic. The -20° in the first clamp shows a bit too much rack:
It may not matter, though, as sometimes you want to remember what’s on the right:
FWIW, the track veering off onto the grass came from a fat-tire bike a few days earlier. Most of the rail trail had cleared by the time we tried it, with some ice and snow in rock cuts and shaded areas.
Contrary to the first picture, I later remounted the camera under the seat rail with its top side downward. The M20 has a “rotate video” mode for exactly that situation, which I forgot to turn off in the fancy new mount, so I rotated the pix afterward.
A 3 mm screw extends upward through the hole in the socket to meet a threaded brass insert epoxied into the shell base, as shown in the uglified M20 model. Despite appearances, the hole is perpendicular to both the socket and the shell, so you can tweak the Look Angle without reprinting the shell.
All in all, the mount works well. We await better riding weather …
The OpenSCAD source code as a GitHub Gist: