The Spherical Surveillance Robot

Abstract

In hazardous industrial and polluted environments where human presence is risky to health, existing robots fail due to instability in detecting air quality. This paper introduces an ESP32-powered spherical surveillance robot, designed for deployment in toxic air zones. Featuring a robust spherical body with dual wheel stabilization, where two large drive wheels for propulsion (movement) and two small caster wheels for balance. The system integrates an ESP32 CAM module for real-time video streaming, navigation and a gas sensor (MQ-Series) for detecting air quality and toxic gases in the environment, all coordinated by the Blynk IOT platform for a custom web dashboard, remote control and data visualization, and a web server for monitoring (Streaming). The design ensures omnidirectional mobility across different rough terrains, detection of the threshold value of carbon monoxide, and an extended operation (~ 2 hours) due to a Li-ion battery. Enabling proactive industrial safety without jeopardizing human safety, the prototype achieve 90% accuracy in navigation and seamless WI-FI range up to 100 ft (20-100 m) for various regions, surpassing Bluetooth technology limitations. The ESP32 system reduces power by 30% and extends wireless reach, advancing a cost-effective surveillance robot for multiple applications.

Introduction

This research presents the design and development of an IoT-based spherical surveillance robot that overcomes the limitations of traditional CCTV systems and conventional mobile robots. Unlike fixed CCTV cameras, the robot can move freely, change its viewing position, and operate in locations that are difficult or dangerous for humans to access.

Need for the System

Traditional surveillance systems have several limitations:

• Fixed viewing angles and locations.
• Inability to respond dynamically to events.
• Vulnerability to damage or tampering.

Conventional wheeled and legged robots also face challenges such as:

• Loss of balance.
• Mechanical complexity.
• Difficulty moving over obstacles.
• Requirement of separate steering mechanisms.

To overcome these issues, the study proposes a spherical robot, whose enclosed spherical shell protects internal components, provides better balance through a low center of gravity, and allows movement in all directions without a dedicated steering mechanism.

System Architecture

The robot consists of three major layers:

1. Control Layer
   • Uses an ESP32 microcontroller as the main processing unit.
   • Handles sensor data, motor control, and wireless communication.
2. Monitoring Layer
   • ESP32-CAM provides live video streaming.
   • MQ-135 gas sensor monitors air quality and detects gases such as CO?, CO, NH?, methane, and SO?.
3. User Interface Layer
   • Blynk IoT dashboard enables remote control and monitoring.
   • A web server streams live video to connected devices.

These layers work together to create a real-time surveillance and monitoring system.

Hardware Components

Key hardware used in the robot includes:

• ESP32 MCU (main controller)
• ESP32-CAM with OV2640 2 MP camera
• L293D motor driver
• Two DC geared motors
• MQ-135 gas sensor
• Dual 7805 voltage regulators
• Rechargeable Li-ion battery (~2000 mAh)

Working Principle

The robot operates as follows:

1. System powers on and initializes all modules.
2. ESP32 connects to Wi-Fi and authenticates with Blynk IoT.
3. Users send movement commands (forward, backward, left, right) through the Blynk application.
4. ESP32 converts commands into PWM signals and controls the motors through the L293D driver.
5. ESP32-CAM continuously streams live video.
6. MQ-135 sensor monitors gas levels and sends data to the cloud.
7. The robot remains in a continuous monitoring and control loop until stopped.

Key Features

• 360-degree omnidirectional movement.
• Remote control through the internet.
• Real-time video streaming.
• Gas detection and environmental monitoring.
• Wireless communication via Wi-Fi.
• Compact, durable, and protected spherical design.
• Fast response time (less than 100 ms latency).
• Approximately 2 hours of continuous operation.

Methodology

The project includes:

• Custom PCB design for compact integration.
• ESP32-based control and communication system.
• Sensor integration for environmental monitoring.
• Real-time data processing and cloud transmission.
• PWM-based motor control for smooth movement.

The ESP32 simultaneously handles motor control, sensor monitoring, video streaming, and cloud communication, making the system efficient and power-conscious.

Conclusion

This paper presented the complete design, PCB implementation, Proteus simulation, and hardware validation of a Spherical Surveillance Robot built on the ESP32 microcontroller. Integrating an ESP32-CAM module, HC-SR04 ultrasonic proximity sensor, MQ-135 gas sensor, L293D motor driver, and two DC geared motors within a custom PCB and protective spherical chassis, the system delivers omnidirectional mobility, real-time MJPEG wireless streaming, autonomous obstacle halting at 15 cm, and cloud-based Blynk IoT monitoring. Hardware trials confirmed 20–25 FPS video at sub-300 ms latency, reliable proximity response, and approximately two hours of battery autonomy. The platform provides a practical, low-cost alternative to static surveillance infrastructure, with demonstrated applicability to security, defence, industrial inspection, disaster response, and environmental monitoring. Future extensions to AI-based detection, GPS patrol routing, and SLAM mapping will further advance the capability of this spherical IoT surveillance platform.

References

[1] B. Rangapur, B. K. Swathi Prasad, and R. Suresh, “Design and Development of Spherical Spy Robot for Surveillance Operation,” Procedia Computer Science, vol. 171, pp. 1212–1220, 2020. [2] A. Diouf, B. Belzile, M. Saad, and D. St-Onge, “Spherical Rolling Robots—Design, Modeling, and Control: A Systematic Literature Review,” Robotics and Autonomous Systems, vol. 175, p. 104657, 2024. [3] T. Akilan, S. Chaudhary, P. Kumari, and U. Pandey, “Surveillance Robot in Hazardous Place Using IoT Technology,” in Proceedings of IEEE ICACCCN, 2020. [4] M. Lakshmi, V. Kommera, S. Kilambi, and J. Malasani, “IoT Surveillance Robot with Night Vision Camera,” IJRPR, vol. 4, no. 11, pp. 739–742, Nov. 2023. [5] A. Dubey, C. M. Gandhamani, M. Meghashree, and N. Rekha, “Surveillance Robot Using ESP32 CAM Module,” IARJSET, vol. 10, no. 6, Jun. 2023.

Copyright

Copyright © 2026 S. D. Mali, Sagar B. Pawar, Pratik A. Pahade, Pritesh S. Khopade. 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.