Quite ingenious, was our first reaction when we spotted the Lockitron keyless locking system. All you need to do is place it over your existing deadbolt and controls the locking mechanism from anywhere in the world. This is made possible with iPhone-control integration. It works with the iPhone 4S and the iPhone 5. In addition to authenticating entry, the lock also senses your proximity by using Bluetooth 4.0. There’s word that this feature may scale up to NFC and Android devices in the future too.
If this isn’t all, Lockitron recognizes and detects particular patterns of knocking, thus notifying you when someone you know is at the door. It will be available only by March 2013 for $149.