This is the key fob for my 2012 Hyundai Sonata in the key wallet I usually carry. Hyundai owners with this key fob sometimes find the trunk on their cars opened by itself, as if haunted. There is a lot of discussion about this problem on owners' forums. Some are certain it is caused by an electrical anomaly in the car's systems or by interference from a stray radio signal. One man carried his key fob in a separate hard case and never had an occurrence of the trunk opening by itself during that time. When he carried his key fob in a wallet, his trunk sometimes opened mysteriously. See the text boxes on the photo. I have found my trunk opened by itself about four times. Each of those was while the car was parked in my garage. I think the little button that is part of the wallet clasp may have exerted pressure on the trunk button on the key fob. This Instructable will show how to make a hard cover for the key fob that still allows easy access to the fob for use.
These key fob covers are available in various colors for about $9 US each. I decided to make my own key fob shield from the cover of an old computer power supply. (The image is from Amazon. To view product information, follow the link.)
Metal shears or snip
Ball peen hammer
Stack of newspaper
Needle nose pliers
Wire feed welder (unless the non-welded version is chosen)
Light gauge steel from a computer power supply case, or something similar