Smart Door Lock

Overview

A smart door lock is a motorized deadbolt that can be locked and unlocked by code, fingerprint, card, phone or mechanical key, and that reports its state to a home network. It replaces a conventional deadbolt in the same door prep, with an exterior module holding the credentials and an interior module holding the motor and electronics. The appeal is keyless entry, remote control and an audit trail of who entered when.

How it works

Credentials are read at the Exterior Escutcheon escutcheon, a weather-sealed outside module carrying a capacitive PIN keypad, a fingerprint sensor, an RFID/NFC reader and status indicators, plus a pin-tumbler Key Override Cylinder for a mechanical key as a last-resort backup. The Interior Escutcheon escutcheon, mounted inside, contains a manual thumbturn, the drive motor, the main control board and the wireless radio.

When a valid credential is presented, the Main Control Board commands the Bolt Drive Motor, a small DC gearmotor, through a Drive Gearbox fitted with a slip clutch that protects the train if the bolt jams or is forced. The gearbox turns a cam and tailpiece that throw the Deadbolt Mechanism, a spring-loaded bolt whose position is read magnetically so the lock always knows whether it is thrown. A reed switch tracks whether the door itself is open or closed.

Connectivity is provided by the Wireless Radio Module, a Wi-Fi/Zigbee/BLE radio that lets the lock be operated and monitored from an app or smart-home hub. Everything runs from the Battery Compartment, a removable tray of 18650 cells, and the two escutcheons are tied together by a ribbon harness through the door.