This small piece of metal comes handy when I have to let go of my camera because I might for a moment need both hands free (like when climbing, or paddling).
I made it from a flat strip of stainless steel, an excellent material that you can find inside the rubber part of (worn) windshield wipers. The best kind of such comes from truck or bus wipers, because of sturdier metal gauge. It will usually cost you either nothing or a cup of coffee, if you simply ask some truck or bus driver to save you the old windshield wipers instead of throwing those away!
Thus, with a pair of wiper rubbers you get four long pieces of high quality steel strips.
Use round-pointed pliers to shape the metal strip as shown. Don't forget to file the material ends smooth before applying the final tightness to the bent places, so as to make the tension of the ends to close with some force against each other.
TIP: the belt slot is four centimeters long, and about three millimeters wide; you can guess-calculate all other dimensions from there.
The purpose of a small plastic piece is to slide down so as to lock the belt slot. Since the belt slot can be opened and closed, the clip can be easily added to the trouser belt, camera bag strap, and even to the swimsuit when snorkeling. Whenever you need to temporarily use both hands for something other than photography, the hook will safely keep your camera ready - and quickly accessible.
Simply hang the camera by its wrist loop to the hook. It will hang directly below the belt slot because of the way it is shaped. At times I used to hang a quiverful of arrows to it (enjoying the 3-D Archery), and it was just as simple to also add a P&S camera with it!
Should you like to see some additional safety (which I found unnecessary), add a small washer to upper side of the belt slot above the open hook end, and slide / let it fall over the hook. This will lock the camera hook against opening, but will require you to finger-lift the washer to remove the camera. In all the years I have been using this clip I have never needed that extra locking piece, and I like to be able to slip the camera off the hook quickly.
DIY Camera / Accessory / whatever Belt Clip