Smart entry system by using Azure cloud platform

The proposed system includes various technological solutions in the field of the Internet of Things, and includes a Raspberry Pi 3B + microcomputer, a motion sensor (PIR sensor), a magnetic switch used as a sensor for door status, an electric lock, Bluetooth technology for detecting the presence of registered devices, MQTT IoT protocol, the Azure cloud platform for user registration and time-based door control. 

The project presents a solution that makes it a lot easier to enter into the IoT environments. The proposed system includes various technological solutions in the field of the Internet of Things, and includes a Raspberry Pi 3B + microcomputer, a motion sensor (PIR sensor), a magnetic switch used as a sensor for door status, an electric lock, Bluetooth technology for detecting the presence of registered devices, MQTT IoT protocol, the Azure cloud platform for user registration and time-based door control. The two linked tables store information about the MAC addresses of registered devices, and their associated identities of the owners, which is managed by an authorized person. All logged data is accessible anywhere, although the system operates within a local network. The development of the system aimed to simplify entering into a room so that the classic universal key for entering a room is not needed when an electric lock is available. The other aim was to provide more security regarding entering IoT environments that are used for the pedagogical process, or represent offices for employees.

.

The basic functionality of the proposed system is to unlock the door using a registered Bluetooth device with an associated MAC address, which is granted permission to enter a specific space and is at the same time within the reach of the lock or near the door of the space. The presence of a person at the door detects a motion detector PIR sensor, which triggers a request to check the presence of the mobile device and the associated Bluetooth MAC address, but is only performed if the door is locked. Namely, the condition of the door is checked with an additional magnetic switch mounted on the door. The status of the doors and the approval of entry is additionally recorded on the Azure IoT Hub cloud platform, which allows monitoring of developments on the door lock from anywhere, although the system itself operates on a local network. In developing the system, we set ourselves the goal of unlocking the door without the need for any additional devices, except a mobile phone, which nowadays follows us every step of the way. Such an idea requires sensory, communication and software upgrades to the existing infrastructure or selected environement. The proposed system also makes it easy to upgrade software and hardware in terms of sensors, controls and motion detection. We wanted to make the system as universal and simple as possible. In doing so, we were limited by the already existing electric lock, which is installed in the space provided.

The program was written in Python in the Raspbian operating system. The hardware was based on the Raspberry Pi microcomputer, with the planned use of its GPIO connectors for the upgrade required. In order to avoid direct soldering of the components to the microcomputer, we decided to upgrade with an expansion module. All models of the Raspberry Pi family have GPIO connectors arranged in the same way, which simplified the development of a microcomputer hardware upgrade. The prototype was developed with the aim of maximizing modularity, or in the form of an extension module (HAT) for this family of microcomputers. This allowed the prototype to be packed into a small housing and also easily replaced with a microcomputer if needed.

With the help of Altium Designer tool we drew the appropriate circuit diagram and planned the print. We included three electromagnetic switches (relays) on the printed matter. One is for controlling the electric lock, and the other two are for the whole system, which runs with the proper software on the microcomputer, independent of our smart lock system. On the printed material we envisaged a connector for a magnetic switch or sensor for the door condition, connection of an electric lock, as well as two connectors for the entire IoT system. We also added holes to better attach the expansion module to the microcomputer. We used the scheme from the technical documentation of the Raspberry Pi microcomputer for the design.