Smart trolley with IoT-based automatic billing and secure locking system

The rapid advancement of the Internet of Things (IoT) has significantly transformed retail automation, enhancing efficiency and customer convenience. This paper presents a Smart Trolley with IoT-Based Automatic Billing and Secure Locking System, which automates product identification, billing, and security in supermarkets. The system integrates an ESP32 microcontroller, RFID technology,and a solenoid locking mechanism to streamline the shopping experience. Customers can add or remove items using the keypad, view real-time billing details, and make secure digital payments. A solenoid lock secures the trolley at the start of shopping and remains locked until successful payment is confirmed. If a customer attempts to leave without completing payment, the system prevents trolley movement, triggering an alert via a buzzer. Additionally, all transactions and shopping data are monitored through the IoT-based ThingSpeak platform, providing real-time insights for both customers and store management. The results confirm the system’s accuracy, efficiency, and reliability, significantly reducing checkout time while enhancing product security and preventing theft. Received on, 10 July 2025 Accepted on, 28 September 2025 Published on, 05 November 2025