I used to keep my keys on a standard carabiner, which I could clip to my belt loop. Most of the time, that worked fine. But every so often, when I unclipped the carabiner from my belt loop, one of the key rings would slip off without me noticing. I had spare keys, so such events were really just a minor nuisance. Then, I got a car with an (exorbitantly priced) keyless entry remote.
One day the inevitable happened, I reached for my keys and the ring with the remote was gone. Staving off the panic, I assured myself that it would turn up. Luckily, the lawn service at my apartment came across it a couple days later... after they ran it over with a riding lawnmower.
Staring at the mangled corpse of my absurdly costly key fob, I resolved to solve my key loss problem once and for all. With the simple hack I describe here, I haven't lost a key since! (Though I have yet to replace the remote.)
This project was made proudly at the i3 Detroit hackerspace.
Step 1: Supplies
* An s-biner (two-sided carabiner)
* A key ring
* Some heat shrink tubing
* A heat gun
* Your keys
Step 2: Attach Key Ring
I like to add a single key ring to the carabiner that all of my other key rings will attach to. This is actually optional, but it makes it somewhat easier to add/remove keyrings.
Step 3: Place Heat Shrink Tubing
Cut a length of heat shrink tubing and slide it onto the body of the carabiner. Then close the clip, and slide it back up over the clip.
Step 4: Apply Heat
Heat up the tubing with the heat gun. The tubing will begin shrinking and forming to the shape of the underlying clip. Make sure to apply heat to all parts of the tubing until it stops shrinking.
Step 5: Finished!
Now you can attach your key rings to the ring on the carabiner, and it is physically impossible for them to fall off! Of course, this won't prevent you from misplacing the whole thing.