- Introduction
- Solution Architecure
- Hardware Designs
- PCB Designs
- CAD Designs
- Network Architecture
- Algorithms
- Security Aspects
- Bill of Materials
- Future Improvements
- Team Members
- Supervisors
- Related Links
- Urbanization has led to quick and efficient parking being vital.
- Human-operated parking lots have a lot of inherent flaws.
- An autonomous parking system could address these issues effectively.
- Manual systems are highly inefficient and Leads to long queues and waiting times.
- It is difficult to manage the allocation of parking spaces.
- Owners cannot easily get an idea of the overall status.
This project aims at eliminating the overheads and inefficiencies associated with manual parking systems in order to provide a comprehensive solution that addresses the concerns of both the consumers as well as the owners of the parking lot.
Our solution architecture consists of Entrance/Exit Nodes, the parking Spot Nodes, the mobile app and Management Portal representing the frontend of the system and the cloud server. The hardware nodes have been given their own power supplies and the all the frontend software and the hardware nodes are connected to the cloud server via Wi-Fi.
A Management Portal for the owners to view and manage their car park. This allows them to easily manage parking spots and collect usage statistics (Daily and weekly statistics). It can be accessed from anywhere and no additional software is required. React JS and Node.js were used in developing this portal as a Single Page Application since it is ideal for the purpose of a dashboard that updates itself in real-time.
The car park users can register for the service through the app. They can reserve parking spots in advance and can make card payments using the mobile app. The app also provides directions to the assigned parking spot once a user is inside the parking lot. The app has been developed using React Native.
These nodes moniter the vehicles at the entrance/exit of the car park. The license plate of the incoming/outgoing vehicles are recognized through the images captured by a camera and processing them in the Raspberry Pi (Python and Tessaract OCR will be used for the Automatic Number Plate Recognition in the Raspberry Pi). It displays the assigned parking spot number in a LCD display. The gate and proximity sensors will control the flow of vehicles.
The purpose of these nodes is to detect the parking spot status using a proximity sensor and send that information back to the server. NodeMCU used will communicate the presence of vehicle to cloud and controls the gate.
The data and control flow of the system gets initiated at the Entrance Node once a user enters into the parking lot. The license plate number of that vehicle will be scanned by the entrance node and it will be sent to the server along with the check-in time. In the meantime, the mobile app will authenticate the user using their location. Once a parking spot is sent by the server, the user will be guided to that spot through the use of clear images using the mobile phone and the necessary updates will be made in the Management Portal. Once the user reaches the parking spot, the Spot Node will check and update the status of the spot (occupied or not). Once the user leaves their assigned spot and reaches the Exit Node, the Exit Node will obtain the license plate number and the check-out time and will send that information to the server. Once the cost has been processed by the server, based on the hourly rate set by the managers of the parking lot, the amount to be paid will be sent to the mobile app while displaying the value on the LCD display.
HC-SR04 ultrasonic distance sensors will sense the incoming vehicle at the entrance node and the digital camera will get the license plate image. This image will be processed at the Raspberry Pi 4 (Python and Tessaract OCR will be used for the Automatic Number Plate Recognition in the Raspberry Pi) and the necessary data will be send to the server. Once a spot number is received from the server, the Raspberry Pi 4 will signal the servo motor to open the gate while displaying the spot number on the LCD display. Each hardware node has an AC-DC power supply attached and the components operate on 5V DC. We will have secure WiFi with standard WPA2 encryption to avoid unauthorized access.
The servo motor will open the spot gate once a spot is assigned to a vehicle. The NodeMCU ESP8266 will decide the parking spot status based on the sensor data received from the HC-SR04 ultrasonic distance sensor and the spot status will be sent to the server. We will be creating an ESP-MESH to create a Wi-Fi mesh network and will be using the in-built Wi-Fi module for connectivity. NodeMCU ESP8266 takes in 5V DC power but operates on 3V3 DC power. Similar to the Entrance/Exit Node, power will be provided using and AC-DC power supply. Unauthorized parties may intercept communication between the nodes and the server. To prevent this, as mentioned before, secure Wi-Fi channels with standard WPA encryption will be used to ensure secure connection to the server.
Most components in the hardware nodes cannot be integrated into a single PCB. Minimal PCBs are required for routing connections to the microcontrollers and resistors.
The PCB designs can be developed for the Spot Node. The designs shown above were developed using Proteus software. The design includes connections to the NodeMCU ESP 8266 and several headers, which can be used to provide connections to the servo motor and the proximity sensor used. An additional header can be used to provide power for this unit via a micro-USB breakout board.
The CAD design shown above is the design developed for demonstration purposes. They were developed using SOLIDWORKS CAD design software. The LCD display is attached to the front of the unit, along with a pair of ultrasonic sensors. A pill-shaped slot was made in the front of the unit in order to extend the tollgate barrier arm, which is controlled by the servo motor from the inside of the unit to the outside. The Raspberry Pi camera holder is fixed at a certain angle in order to get a clear and uninterrupted view of the license plate numbers of incoming vehicles. The camera holder can be 3D printed if possible. The thin slot should be made within the inside of the holder in order to insert the cable connecting the camera and the Raspberry Pi.
The CAD designs for the Spot Node were developed using Autodesk Fusion 360. The design consists of two pillars, one solid and the other hollow. The hollow pillar has a servo motor connected to the top of it such that the Spot Node gate can be controlled through this motor. The hollow pillar encloses the NodeMCU ESP8266 and the connecting wires. The HC-SR04 ultrasonic sensor attached to the hollow pillar can be used to detect the occupancy status of the parking spot. Additional CAD models for the NodeMCU ESP8266, the servo motor, the HC-SR04 ultrasonic sensor, and the sensor holder have been imported using the GRABCAD community library.
For the backend we will be using the MERN Stack (MongoDB Database, Express.js web framework, React.js Frontend Framework, Node.js server). The backend is primarily handled by a Node.js web server running on an AWS cloud VM instance. The Express web framework is used to simplify the development process since it abstracts away things like HTTP request handling, parsing URLs etc. In-built Express methods are used to develop the REST API that the web application and the mobile app uses to communicate with the server. The REST API endpoints will use HTTPS to leverage TLS/SSL encryption for the communication with the server.
A MongoDB database on an Atlas instance is used for data storage. The Mongoose data modelling library is used to provide a layer of abstraction to the connection between the Node server and the database. The Atlas service provides the ability to do routine backups of the database. The hardware nodes will communicate with the server using the MQTT protocol. The server will interact with the hardware nodes using AWS IoT Core. MQTT can be configured to use TLS/SSL encryption so that the communication is secure.
The server runs the spot picking algorithm (Python script) as a child processes using the child-process library. Reservation handling is done by running it as a separate JavaScript file, which handles reservations one hour prior to the reservation time. Owners can observe reservations through the management portal. Records of usage of the parking lot are stored in the database and the temporary storage has a lifetime of three months. (Reservations and spot assignments.) Cors library is used to enable CORS (Cross-Origin Resource Sharing) for security. This allows us to limit access to the API based on the origin. Bcrypt is used for password hashing which uses the blowfish cipher with ten salting rounds to prevent attacks without a large hit to performance. Jsonwebtoken is used for user authentication. This generates a session token for a registered user when they log in that can be used to authenticate the user with the credentials stored in the database. Details of the REST API endpoints for the server side are available in the project repository.
During a power outage, if the car park management decides to keep the car park open despite the hardware nodes being down, they can manually enter the data into the system through the management portal to keep the system up-to-date so that it can recover properly and continue operation once it is back online. Hardware node online/offline status will be detected by the transmission of an MQTT “heartbeat” message every 5 mins.
Whenever a customer arrives at the Entrance Node, the backend server is expected to find a suitable unoccupied spot (unless it is reserved) for the customer. This process is done considering the possibility of a customer parking at the wrong spot once they are inside the parking lot. To avoid such a situation, the spot picking algorithm tries to find the furthest spot from the last allocated spot for the most recent user.
It is possible for registered car park users to make reservations through the mobile application. For a user to make such a reservation, the following prerequisites need to be satisfied: the reservation must be on the same day, have to be made more than one hour before the reservation time, reservations are not a guarantee for a parking spot.
Our system security is mainly characterized by the following elements. Bcrypt has been used for password hashing in order to securely store login credentials of the users. CORS (Cross-Origin Resource Sharing) is used for security to limit access to the API based on the orgin. Atlas will limit ingress access to requests coming in from the server’s IP address (Server communicates with Atlas instance over HTTPS). Access Management Control is deployed within the system by covering the 3A's; Authentication, Authorization and Accountability. Jsonwebtoken is used for user authentication, while the location of the user is checked at the entrance. We only allow GET method access for the mobile app users using CORS. For authentication we wiil be passing the auth-token for every API request as a header. We are using Transport Layer Security (TLS) to secure the connection and the data. This technology encrypts data before it is sent from the client to the server, thus preventing some common hacks. Without TLS POST requests will be visible so their network traffic is vulnerable to packet sniffing and man-in-the-middle attacks. Utilizing Secure Socket Layer (SSL) encryption was done while using Nginx to handle TLS.
Validator.js is used in order to validate user input to limit SQL injections and XSS attacks. This is done to validate every input for the frontend since some attackers can send sql commands or harmful java script code to execute. Validatorjs is used to prevent such attacks by checking whether the input is a valid email. Using npm to manage our application’s dependencies is powerful and convenient. But the packages that we use may contain critical security vulnerabilities that could also affect our application. To avoid such vulnerabilities, we will be using Snyk which offers both a command-line tool and a Github integration that checks our application against Snyk’s open source vulnerability database for any known vulnerabilities in our dependencies. X-Powered-By reveals information about the technologies used in an app. Therefore, to avoid outsiders exploit server security weaknesses of our server technology we will be disabling this header.
- More detailed statistics for the management portal to make things easier for management. Expand the data storage of the usage statistics and provide an easy way to manage logs.
- Provide a way to give the location of the parking spot to the car park users in a more dynamic manner to make the mobile app more user friendly.
- Add a feature in the mobile app to assist the car park users to the parked spot once they get back to the parking lot.