Autonomous Following and Repositioning Shopping Cart

Abstract

The present-day retail market demands the implementation of automation technologies that provide convenience and efficiency in shopping. This paper focuses on the design and development of an intelligent smart shopping cart that is capable of autonomously tracking the user and implementing the feature of self-billing. The system utilizes the Bluetooth Low Energy (BLE) signals transmitted from the customer’s smartphone to estimate the relative position of the user using the Received Signal Strength Indicator (RSSI) technique. The system utilizes the ESP32 module to process the signals and move the shopping cart using DC motors connected to a motor driver module. The system also utilizes ultrasonic sensors for real-time obstacle detection. Moreover, the system provides the facility of billing using an Android-based application and Firebase cloud database. The proposed system reduces the manual effort and the long queue at the billing counter, providing an efficient shopping experience.

Introduction

The rapid advancement of IoT and embedded systems is reshaping retail, yet traditional shopping carts remain manually operated, causing inconvenience—especially for the elderly and physically challenged—and inefficiency due to time-consuming billing queues. Existing smart cart solutions often face high costs or lack autonomous mobility.

To address these issues, the paper proposes an autonomous smart shopping trolley system that:

• Tracks users via Bluetooth Low Energy (BLE) and RSSI signals to follow them automatically.
• Uses ultrasonic sensors for obstacle detection and safe navigation.
• Employs an ESP32 microcontroller for motor control and navigation.
• Integrates an Android app for real-time barcode scanning and automatic billing, eliminating traditional checkout queues.

The literature review highlights past IoT-based smart carts using RFID or mobile apps, noting limitations like high costs, lack of autonomous following, and absence of obstacle avoidance.

Proposed System Components:

1. BLE-based tracking for user localization.
2. Obstacle avoidance system for safety.
3. Motor control unit for autonomous movement.
4. Android-based billing application for efficient checkout.

Operation: The trolley calculates direction using RSSI comparisons and navigates using motor commands, prioritizing obstacle avoidance over following.

Hardware: ESP32 microcontroller, ultrasonic sensors, L298N motor driver, DC gear motors, battery with buck converter.

Advantages: Hands-free shopping, reduced billing queues, accessibility for elderly/disabled users, low-cost implementation, and scalability.

Results: The prototype successfully followed users, avoided obstacles, and managed real-time billing efficiently in indoor tests. Minor RSSI fluctuations can be mitigated with filtering techniques.

Conclusion

This paper has discussed the design and implementation of a BLE-based autonomous shopping trolley system for billing purposes. The proposed system has efficiently utilized IoT technology, embedded systems, and mobile application development to enhance the overall shopping experience. The proposed system has successfully implemented a reliable human following capability, efficient obstacle avoidance mechanism, smooth navigation, and a billing system. These features can efficiently reduce manual effort and enhance overall efficiency. Moreover, the proposed system has also been found to be cost-effective, scalable, and suitable for deployment in a real-world environment. With further advancements in localization accuracy and automation techniques, this proposed system has strong potential to contribute to future smart retail technology.

References

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Copyright

Copyright © 2026 Dr. Joly M, Alwin C K, Abhiram K, Krishnadas P D, Midhul Krishna M M. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.