Implementation of Raspberry Pi Mini-Computer

Study Case Implementation of Raspberry Pi Mini-Computer for RFIDBased No Standing Zone Violation Detection System Michael Kurniawan (2018123456) University of Cincinnati, 2600 Clifton Ave, Cincinnati, OH 45221, United States kurniaml@mail.uc.edu Abstract This research developed a prototype system that functions to reduce traffic congestion by detecting vehicles that stop for too long in areas marked No Standing/No Stopping in accordance with traffic regulations in the United States. The system is built using a Raspberry Pi 3 Model B mini-computer running the Raspbian operating system, and utilizes RFID as a vehicle identification sensor connected to a database containing vehicle registration information. When a vehicle is detected to have stopped beyond the specified time limit, the system automatically enters the violation into the database to be processed in accordance with U.S. Department of Transportation policy. This prototype shows that the integration of RFID and Raspberry Pi can be used to record and store violation data in real-time. Keywords: Raspberry Pi; traffic violation system; Python webserver; RFID MFRC522 INTRODUCTION Currently, developing countries are experiencing rapid growth in various sectors, including an increase in the number of motor vehicles. The growth of motorized transportation provides ease of mobility, but it is not always accompanied by adequate road infrastructure expansion. This gap has led to the emergence of traffic congestion points in various regions. In addition, vehicles that stop indiscriminately—including ride-hailing services such as Uber and public transportation—often worsen traffic conditions, especially in high-density areas. As an analogy to the Indonesian context adapted to the United States environment, similar conditions also occur in several major US cities such as New York City, MICHAEL KURNIAWAN 1 Study Case Chicago, and Los Angeles, where vehicle volume is increasing faster than road capacity expansion. Data from the U.S. Department of Transportation shows that the growth of private vehicles and app-based transportation services continues to increase every year, necessitating technology-based traffic management innovations. To address these issues, this study designed a prototype device that helps monitor and prevent vehicles from stopping for too long on roads with high density levels. This device was developed under the title “Prototype of a Raspberry Pi Mini-ComputerBased Congestion Prevention System.” Radio Frequency Identification (RFID) Radio Frequency Identification (RFID) is a technology for identifying objects or individuals using radio wave transmission. RFID works using a tag or transponder that stores data, as well as an RFID reader that sends signals and receives responses from the tag. In this prototype, RFID is used as a vehicle identification sensor connected to a database system. Figure 1 shows a basic illustration of how the RFID sensor works. Figure 1. RFID System The RFID system has four main components: Tag An RFID tag consists of an integrated electronic circuit and antenna with internal memory. This memory can contain read-only data (e.g., a unique serial number) or readwrite data. Based on their power source, tags are divided into two types: a. Active Tags These have an internal battery power source, enabling signal transmission over longer distances. Their drawbacks are larger size and higher cost. b. Passive Tags These lack an internal power source and obtain energy from the radio waves emitted by the RFID reader. They are smaller and cheaper, but have a shorter MICHAEL KURNIAWAN 2 Study Case read range. Reader The RFID reader acts as an interface between the software application and the signal transmitting antenna. The reader emits radio waves that are then captured by the tag, enabling wireless data communication. Application Software An application on a computer or server that reads and processes data from tags via an RFID reader. Both tags and readers are equipped with antennas to transmit and receive electromagnetic signals [1]. MFRC522 Module Specifications The MFRC522 RFID module operates on MIFARE Type A 13.56 MHz (ISO/IEC 14443) technology and was developed by NXP Semiconductor, with a security system in the form of Crypto-1 for the Classic series and Triple-DES/AES for the DESFire series. Technical specifications of MFRC522: • Chipset: MFRC522 Contactless Reader/Writer • Frequency: 13.56 MHz • Reading distance: < 50 mm • Access protocol: SPI @ 10 Mbps • RF transmission speed: 424 kbps (bi-directional) / 848 kbps (unidirectional) • Supported cards: MIFARE Classic S50/S70, Ultralight, DESFire • Security features: Framing & Error Detection (parity + CRC) • Internal buffer: 64 bytes • Power supply: 3.3 V • Current consumption: 13–26 mA during operation, < 80µA in standby mode • Operating temperature: –20°C to +80°C • Dimensions: 40 × 50 mm Figure 2. MFRC522 RFID module MICHAEL KURNIAWAN 3 Study Case Raspberry Pi Raspberry Pi is a credit card-sized single-board computer (SBC) that has all the basic functions of a full computer. This device uses an ARM-based System-on-a-Chip (SoC) integrated on a PCB, and utilizes a microSD card for booting and long-term data storage. In the context of the United States network, this device is often used in Sub Transmission Networks environments for edge computing applications [2]. Raspberry Pi 3 Figure 3 shows the Raspberry Pi 3, the third generation in the Raspberry Pi family. This device is equipped with 1 GB of RAM and a Broadcom VideoCore IV GPU with a frequency of 250 MHz. The Raspberry Pi 3 was released as the successor to the Raspberry Pi 2 Model B in February 2016. The advantages of the Raspberry Pi 3 over previous generations include: • ARMv8 64-bit quad-core CPU with a speed of 1.2 GHz • 802.11n Wireless LAN • Bluetooth 4.1 • Bluetooth Low Energy (BLE) Like the Raspberry Pi 2, this device has 4 USB ports, 40 GPIO pins, a full HDMI port, an Ethernet port, a 3.5 mm audio jack integrated with composite video, a camera interface (CSI), a display interface (DSI), a push-pull microSD slot, and full support for VideoCore IV 3D Graphics. The Raspberry Pi 3 has the same physical form factor as the Raspberry Pi 2 and is compatible with the Raspberry Pi 1 and 2. This device is recommended for projects that require very low power consumption. Figure 3. Appearance of the Raspberry Pi 3 Model B MICHAEL KURNIAWAN 4 Study Case Figure 4. GPIO Pin Layout on the Raspberry Pi GPIO is a series of 40 pins with various functions and is one of the most vital features in the Raspberry Pi, as it provides a physical interface between the device and the outside world. At a basic level, GPIO pins can be treated as digital switches that can read (input) or send signals (output). Figure 4 shows the GPIO pin configuration. Of the total 26 GPIO pins that are commonly used, the Raspberry Pi provides: • 2 5V power supply pins • 2 3.3V power supply pins • 5 ground pins • 17 input/output pins GPIO pins can be controlled using various methods, including bash scripts, Python, and various other programming languages. In addition to input from physical switches, GPIO can also receive data from various sensors or other computing devices. Figure 5 shows the complete configuration of the GPIO port on the Raspberry Pi [3][4][5]. Python The name of the Python programming language does not come from the animal, but was inspired by the BBC comedy show Monty Python's Flying Circus. Python was developed by Guido van Rossum from Amsterdam, before eventually becoming a programming language widely used by software engineers around the world. Since its public release in 1991, Python has grown rapidly through the support of global communities such as the Python Software Foundation (PSF), online discussion groups, and various developer organizations [6]. Python is open-source, available complete with source code, debugger, profiler, GUI interface, system features, and libraries for database management. Python can be run on various operating systems such as UNIX, macOS, Windows, and Linux. Python's philosophy includes several principles, including: • Coherence – syntax that is easy to read, write, and maintain • Power – supports advanced functionality • Scope – flexible and suitable for various applications MICHAEL KURNIAWAN 5 Study Case • Object-Oriented – supports object-oriented programming • Open Source – free to use, including for commercial applications Python is known for the term “batteries included,” which means that its standard library provides modules for almost all needs, from web servers, data processing, file compression, to network communication. The interactive shell environment in Python allows users to try out lines of code directly, test function behavior, and perform debugging. IDLE Python provides a simple Integrated Development Environment that is ideal for beginners. In IDLE, the command history cannot be accessed with the up arrow as in a Linux terminal. Instead, users can move the cursor to an old command and press Enter to run it again. Shortcuts are also available: • ALT+P → previous command • ALT+N → next command Basic Elements of Python Programming 1. Input – receives data from I/O units such as keyboards using the input() function in Python 3.x. 2. Data – includes numeric types, strings, lists, tuples, and dictionaries. 3. Operation – arithmetic operations, assignment, and other computations. 4. Output – displaying data using the print() function. 5. Conditional Execution – branching using if, elif, and else. 6. Looping – repetition using for and while. 7. Subroutine – functions or methods defined with def. Pip Pip is a Python package manager that functions like an app store for Python modules and libraries. Through pip, users can search for, install, update, and remove packages needed in application development. Virtual Environment Virtualenv is a tool for creating isolated Python environments. Isolation means that the environment has its own set of packages and modules that cannot be accessed directly by programs outside that environment. Python programs run in virtualenv use specific module versions installed in that environment, while programs running without virtualenv can only use global system modules (for example, those located in directories such as /usr/lib/python3.x/site-packages on modern Linux distributions). When installing modules using pip without a virtual environment, the packages will MICHAEL KURNIAWAN 6 Study Case be installed globally to the system's site-packages directory. Virtual environments are created to ensure that each application has its own package version without interfering with other applications that may require different versions. Therefore, virtualenv (or its modern alternative, venv in Python 3) is very useful for ensuring that each application has its own package isolation. [7] Figure 9. Overview of how virtual env works Figure 10. Module separation by virtual env Serial Peripheral Interface (SPI) Serial Peripheral Interface (SPI) is a popular serial communication protocol that is simple and easy to implement. Compared to USART or UART, SPI tends to be easier to set up for many hardware applications. Figure 6 shows an example of hardware setup for SPI. After SPI became the de facto standard, this protocol became available in many microcontrollers such as 8051, ARM, PIC, and AVR, enabling connections between two microcontrollers with different architectures. SPI applications include wired data transmission, certain wireless modules (e.g., 2.4 GHz modules), microcontroller programming (.hex file upload), and interfaces to sensors and other peripheral devices such as IMUs, joysticks, and compasses. The advantages of SPI include: • A simple interface for setup and data transmission. • Full-duplex communication (simultaneous sending/receiving). • Relatively low power consumption for some implementations. MICHAEL KURNIAWAN 7 Study Case The disadvantage is that it requires more physical lines (pins) than other protocols such as I²C, thus consuming more pins on the microcontroller. Master and Slave in SPI In SPI, one device acts as the master (initiating communication and controlling the clock), while one or more other devices act as slaves. SPI communication is typically full-duplex: while the master is sending data, the slave can also send data at the same time. SPI typically uses four main signals: • MOSI (Master Out Slave In) — data line from master to slave. • MISO (Master In Slave Out) — data path from slave to master. • SCK (Serial Clock) — clock signal provided by the master for synchronization. • SS / CS (Slave Select / Chip Select) — active-low signal to select a specific slave; when SS = 0 (low), that slave is active. Figure 13. Single master SPI interface diagram Data Transactions in SPI Mode Data exchange in SPI is performed using a shift register mechanism (generally 8 bits per register, although some architectures support 10 or 12 bits). The master configures the clock and ensures that the transfer speed is the same between the master and slave (can reach several MHz). To begin, the master pulls SS low on the selected slave, then generates clock pulses; each clock pulse shifts one bit in the master and slave registers, so that after eight pulses a full byte is exchanged. When there is still data to be transferred, the shift registers are reloaded and the process repeats until the master ends the session by returning SS to high. At the bit level, the bit shift sequence is illustrated in Figure 8, Figure 11, and Figure 12, where each clock pulse causes the bits from register A (master) and register B (slave) to shift and interleave into their correct positions. After eight clock pulses, the MICHAEL KURNIAWAN 8 Study Case entire byte has been copied between devices, demonstrating the full-duplex nature of SPI. Figure 6. SPI Hardware Setup Figure 7. SPI Data Transfer 1 Figure 8. SPI Data Transfer 2 Figure 11. SPI Data Transfer 3 Figure 12. SPI Data Transfer 4 Multiple-Slave SPI Mode SPI supports configurations with multiple slaves, but there is only one master. In this configuration, the master's MOSI, MISO, and SCK lines are paralleled to all slaves, while each slave has a separate SS/CS line controlled by the master. The master selects the slave to communicate with by pulling the slave's SS to logic low (active-low). It is MICHAEL KURNIAWAN 9 Study Case important not to pull down the SS of more than one slave at a time to avoid data collisions; the master must wait for the transfer to complete on one slave before selecting another slave. Figure 14. SPI bus with multiple slaves Figure 5. Raspberry Pi 3 Model B GPIO 40 Pin Block Pinout SQLite SQLite is a lightweight, ACID-compliant, and small relational database management system. This project was developed by D. Richard Hipp and is in the public domain. Unlike traditional client-server databases, SQLite acts as a library that is directly linked to the application so that all database operations are performed through local API calls, reducing overhead and latency. All database components—schema definitions, tables, indexes, and data—are stored in a single file. This simple design often locks the entire file during transactions to maintain consistency. SQLite implements most standard SQL-93 features, including atomic transactions, consistency, isolation, durability (ACID), triggers, and complex MICHAEL KURNIAWAN 10 Study Case queries. The absence of strict type checking allows numeric values to be stored as strings, a feature that is considered useful for quick scripts but also considered a shortcoming by some. [10] SQLAlchemy SQLAlchemy is an SQL toolkit and Object Relational Mapper (ORM) for Python that provides flexibility, enterprise-level persistence patterns, and full control over SQL generation. SQLAlchemy treats databases as relational algebra engines, allowing Python classes to be mapped to database tables and efficient composable SQL statements to be constructed. Its ORM component is optional but popular: it allows the object model to evolve independently of the database schema. Instead of hiding SQL, SQLAlchemy transparently exposes the SQL generation mechanism so that developers can automate repetitive tasks without losing control over how SQL is generated and executed. [11] Data Model Concepts Entity Relationship Diagram (ERD) An Entity Relationship Diagram (ERD) is a model used to document an organization's data by identifying the types of entities and the relationships between entities. ERDs describe the structure of the data network stored in the system in an abstract manner and show the relationship between an entity and its attributes in an integrated system. System designers use ERDs to model data that will later be translated into a physical database. This model aids the analysis and design process by showing the types of data needed and how the data is related. Entity An entity represents a basic object that is relevant to the system. These objects can be individuals, objects, or concepts whose information needs to be stored in a database. Attribute An attribute is a characteristic or description of an entity. In general, attributes are depicted using an ellipse (oval) symbol. Attributes must be named using singular nouns that are easy to understand and have clear meanings. Each attribute is connected to the related entity through a connecting line. Relation A relation is a relationship or transaction that occurs between two or more entities whose information needs to be stored in a database. There are several variations of relations: • Binary Relation: a relationship between two sets of entities (for example: MICHAEL KURNIAWAN 11 Study Case student–enrolls–course in the context of the University of Cincinnati). • Unary Relation: a relationship that occurs within the same set of entities (single relation). • N-ary Relation: a relation involving three or more entities. Relational cardinality indicates the maximum number of entities that can be related to each other: • One-to-One (1:1) • One-to-Many (1:N) • Many-to-Many (M:N) This cardinality model describes the limitations of relationships between entities in accordance with real-world situations in information systems. Flask With the development of information technology, web applications today not only function as a medium for providing static information, but are also capable of processing data dynamically. This requires powerful, secure, and reliable software on the server side (server-side scripting). Some of the languages or platforms commonly used in the United States include Python, PHP, ColdFusion, Perl, and ASP.NET. Flask is a popular Python-based microframework due to its lightweight and flexible nature. Flask does not provide a built-in abstraction layer for databases or form validation, but it supports various third-party extensions that can add features such as ORM, authentication, file upload management, and others. This framework is used in various large applications such as Pinterest, LinkedIn, and the Flask web community itself [12]. METHOD Basic Concepts of Tool Design The selection of hardware and software is the initial stage in system implementation. These basic concepts serve as guidelines for designing and determining the supporting components required in the system design. Prototype Design of a Raspberry Pi-Based Traffic Jam Prevention System The system prototype was developed using the Fritzing V0.9.3b application to assist in creating schematics because the application provides a variety of ready-to-use components. The database was designed using SQLite because it is lightweight, easy to MICHAEL KURNIAWAN 12 Study Case use, and compatible with Raspberry Pi and the RFID sensors used. SQLite supports integration with various APIs, is stable, does not require complex configuration, and has good performance. Figure 15. Raspberry Pi Schematic Figure 16. Circuit Diagram Hardware Design a. Control Computer System Design The system is controlled by a Raspberry Pi 3 Model B mini-computer. The pins used to connect the MFRC522 RFID module are: • Pin 1 → 3.3 V (power supply) • Pin 22 → Reset • Pin 19 → MOSI • Pin 21 → MISO • Pin 23 → SCK • Pin 24 → SDA • Pin 6 → Ground The complete connection is shown in Figure 16. MICHAEL KURNIAWAN 13 Study Case b. RFID Reader Design The RFID Reader functions as a tag scanner. When a tag is recognized, the system will read its unique ID and match it in the database. If the ID is not yet registered, the system will record it as a new entity; if it is already registered, the identity data and time will be updated. Software Design a. Raspberry Pi Installation Raspberry Pi uses the Raspbian operating system. Installation is done via a microSD card. The webserver system is created using Flask, while data storage uses SQLite connected via SQLAlchemy. All RFID scan data is stored in a database and can be displayed via a Python-based web interface. b. System Design and Development The database is designed based on the RFID Tag structure, which contains an identity number. When a vehicle is detected entering the surveillance area, the tag ID is scanned and recorded along with a timestamp. SQLAlchemy utilizes SQLite as the database engine, enabling the system to operate as a Python-based web server with a clean and efficient data structure integration. RESULTS AND DISCUSSION RFID Testing This test was conducted to determine the response of RFID tags to RFID sensors and Raspberry Pi mini-computers. The testing process used a simple test script, then the RFID tags were attached to the MFRC522 module. The reading results were displayed through the terminal on the Raspberry Pi, and each tag generated a unique code as its identity. Because the sensor used was the MFRC522 type, the reading distance was limited to less than 5 cm. With these characteristics, the developed device was still in the prototype stage. Figure 17. Test script testing with RFID tags. MICHAEL KURNIAWAN 14 Study Case Overall Testing Overall system testing was conducted to verify the integration between the RFID sensor, Raspberry Pi, and database. The RFID Tag was placed on the MFRC522 sensor to observe the response of the application and database. The Flask web server was activated with the command: flask run --host=0.0.0.0 The --host=0.0.0.0 argument is used so that the server can be accessed from other devices on the local network, not just from localhost. Figure 18. Display after the flask run command Each RFID tag must first be registered through the registration page as shown in Figure 19. Figure 19. Vehicle Registration Form The data display (Figure 20) shows information about registered vehicles. This information is analogous to the data contained in the Vehicle Registration Certificate from the DMV in the United States, such as registration number, owner name, owner address, vehicle model, type, class, engine displacement, chassis number, engine number, vehicle color, fuel type, license plate color, registration year, and others. A special addition to this system is the RFID Tag ID as the vehicle's digital identity. MICHAEL KURNIAWAN 15 Study Case Figure 20. Display of registered vehicles with RFID Figure 21 shows the terminal response when a registered vehicle’s RFID commits a violation. The system displays the time of the violation, the RFID IDE, the vehicle registration number, and the owner’s name. Unregistered RFIDs are still read by the sensor, but the system does not enter the data as a violation. Figure 21. Script response to registered RFID tags The list of recorded violations is displayed through a web interface (Figure 22) in a more user-friendly manner, making it easier for officers to monitor violation records in the system. Figure 22. List of violations stored in the database Overall, the system works as designed, although there are still limitations in the hardware and software. The integration of RFID reading, vehicle data storage, and the display of violation lists via the web is running smoothly and is easily accessible. MICHAEL KURNIAWAN 16 Study Case CONCLUSION Conclusion Based on the results of testing the Raspberry Pi-based congestion prevention system prototype, it can be concluded that Raspberry Pi is capable of managing RFID sensors and simple databases without requiring additional devices other than Python libraries. This prototype system works stably according to the developed script and can be used as a basis for monitoring vehicles that stop for too long in areas where stopping is prohibited or traffic conditions are congested. This system has the potential to be a useful tool for traffic officers in handling congestion more efficiently. Recommendations This prototype is useful for traffic environments prone to congestion, but it still has a number of limitations, especially with RFID sensors that have a short reading distance. The SPI port on the Raspberry Pi is also not yet optimal for multiple slave configurations without the addition of external components. For further development, it is recommended to: 1. Use RFID sensors with longer range and higher accuracy. 2. Improve the SPI architecture using an external controller to support multi-slave configuration. 3. Optimize the Python script, Flask API, and database structure to be ready for long-term use and larger scale. REFERENCE MICHAEL KURNIAWAN 17 Study Case MICHAEL KURNIAWAN 18