IoT-Enabled Vacant Parking Slot Detection System Using Inkjet-Printed RFID Tags

It is challenging for motorists to manually search for a parking slot in a crowded parking area. Conventional methods for locating vacant or occupied space are regarded as inefficient and unreliable. In this work, an Internet-of-Things (IoT)-enabled vacant parking slot detection system is developed and tested using low-cost inkjet-printed passive ultrahigh-frequency (UHF) radio frequency identification (RFID) tags. The working principle of the proposed system is to analyze the backscattered signal strength from the tags at the receiver side for vehicle presence/ absence detection in the parking slots. First of all, we propose a low-cost passive tag optimized to work in UHF RFID-band pasted on plastic material display for parking slots. The data collected by the RFID reader from the tags is sent over message queuing telemetry transport (MQTT) protocol via Scotland 5G-network to the MongoDB database using a Python module Pymongo for decision-making and display of vacant parking slots to the motorists. A Python-based web-app extracts data from the database and shows it on a web-app display using the embedded JavaScript template (EJS) for each slot. Experimental observations conducted at parking slots in the presence of vehicles indicate a drastic reduction in the received-signal-strength-index (RSSI) value at the receiver end, which implies that RSSI signal drop can be utilized for the detection of vehicle presence in the parking slot. The suggested approach aims to facilitate the economical and effective location of available parking slots. The test results for the proposed system are recorded and presented, demonstrating its significant performance and showing great accuracy for the tested scenarios.