I wanted to write about tileMate since some time now. I got this small device few months ago at a corporate event and immediately declared it useless. But after using it for some months now I have found it utterly useful.
As a person who is unorganized and needs to move fast between classes and my part time work tileMate has contributed to ease my pain. I am often forgetful about my keys. So I attached it to my house keys. 
TileMate is a miniature device which one can attach to keys or camera or anything and install the mobile app from app-store. The small tile seems to be loaded inside with Bluetooth, GPS and miniature loudspeaker. And when I forget where I kept my keys (usually in the mornings) just double tap on the tile mobile-app and the tile starts ringing. I can also check the location of my keys which is attached to the tile on the mobile-app. You can also double tap on the tile to find your mobile phone(if one loses the phone) if the Bluetooth is ON.
Simple device made ingeniously.