Handy

Lockitron installs over almost any deadbolt, so users do not need to add anything special in their door. Besides installing more quickly, this also allows renters to put the device on their door. The part of the deadbolt that turns slides inside the Lockitron, and it unlocks at the user's request.

The device is always connected to the internet using Wi-Fi, which allows users to get access to it from anywhere in the world. Lockitron can be used differently depending on what device the user is using. For iPhone 4S and iPhone users, the locks can open automatically as the user approaches them, thanks to Bluetooth 4.0 technology. For Android phones with NFC, they can simply wave their device in front of the Lockitron, and it will turn the deadbolt. Other internet-enabled phones can use it via their mobile web browser. Even users without smartphones can send a text message to Lockitron to unlock their door, for a monthly fee.
The main user can grant access to guest, so they can come and go freely for a time period defined by the owner. This is great if friends are coming over or if someone is house sitting while the owner is away.
The device has a knock sensor. If someone knocks on the door, the homeowner will receive a notification informing them of an arriving guest. It also has an unlock sensor, so if someone uses a traditional key to gain access to the house, the main user will be notified. Lockitron runs on two AA batteries which should last about a year. It will send an alert when the batteries are running low. Obviously, having the device die when a user is away would end poorly, so this notification is quite important.

Also look at http://www.bdhhi.com/accesscontrol/

Unikey: http://www.unikeytech.com/

LOCKITRON https://lockitron.com/help/media