This is a "generic" flash/hot shoe-mounted adapter for a digital camera's shutter to be remotely triggered using a standard mechanical cable release.
I don't actually recommend doing this -- it's usually better to use the wired or wireless electronic remote means provided by your camera. However, I've gotten more than a few cable releases thrown-in with camera/lens lots purchased via eBay, and if you've got these nice cable releases, why not use 'em? This adjustable adapter mounts in the flash/hot shoe to allow positioning the cable above the unthreaded shutter button of the camera so that the extending center portion of the cable release can trigger an exposure.
The cable releases generally have an odd tapered thread, which I have implemented based on the V2 OpenSCAD design in https://www.thingiverse.com/thing:186443 ... and thus this inherits its attribution, non-commercial, license. All other aspects are my original design.
Any Brand PLA
Black / Copper
All three parts are trivial prints easily made on any cheap FDM printer -- despite each including small 3D-printed threads. However, the forces experienced by the parts in operation are surprisingly non-trivial. The bar (shown in copper PLA) will flex, but that does no harm. PLA is probably better than ABS for these parts; PLA flexes less than most alternative materials. The only potential issue is that the strength of the 1/4-20 thread's connection to the flash/hot shoe mount can weaken over time, and potentially fail -- so make sure to use at least 3 walls for that part to give better bond strength. Also note that the screw threads are made with a deliberate tolerance to prevent binding of PLA against PLA.
Use Of This Adapter
Use of the adapter is quite simple. Start by carefully screwing the cable release's tapered thread into the bar (shown in copper). Once screwed in, you should be able to freely press the cable release and see the center pin of the cable emerge; it should retract again when you stop applying pressure. Slide the mount all the way into the flash/hot shoe. Place the bar's slot over the upward-pointing 1/4-20 thread of the mount and position the bar so that the center pin will hit near the middle of the camera's shutter button. Finally, lock the bar in position using the knurlled knob/wheel. Enjoy!