Industry 4.0 has revolutionized the manufacturing sector, ushering in a new era of automation and digitalization. In this article, we explore the synergistic potential of robotics, sensors, IoT, and machine learning in unleashing a smart automation system for Industry 4.0. We begin by providing an overview of Industry 4.0 and its implications for the manufacturing sector, highlighting increased automation, data-driven decision-making, and improved efficiency as key benefits. We then delve into the role of robotics, discussing their applications in manufacturing and advancements for Industry 4.0, such as collaborative robots, autonomous systems, and adaptive manufacturing. Next, we explore the contribution of sensors in Industry 4.0, including their importance in industrial applications, types of sensors used, and the role of sensor networks in data collection and analysis. Moving on to IoT, we examine its relevance in the industrial context, the role of IoT-enabled devices in connectivity and communication, and the use of IoT platforms for seamless integration of data and systems. Additionally, we explore machine learning and its applications in Industry 4.0, discussing supervised, unsupervised, and reinforcement learning algorithms, as well as their use in predictive maintenance, quality control, and optimization. We then highlight the potential benefits of synergizing robotics, sensors, IoT, and machine learning, including enhanced efficiency, improved decision-making, and adaptive manufacturing. We also address the challenges and considerations for successful integration, such as data compatibility, security, and interoperability. Furthermore, we present real-world case studies and frameworks for integrating these technologies. Finally, we discuss emerging trends, ethical and security considerations, and the potential impact on the workforce, emphasizing the need for upskilling. This article provides valuable insights into the transformative potential of a smart automation system and offers a glimpse into the future of manufacturing in the digital age.