Raspberry Pi in Industry 4.0: A Comprehensive Review of Applications in Industrial IoT and Digital Twin Systems

The transformation of industrial systems through Industry 4.0 technologies has sparked a growing interest in decentralized, intelligent, and cost-effective hardware solutions. Among them, the Raspberry Pi family of single-board computers—ranging from the ultra-compact Pico and Zero models to the more powerful Raspberry Pi 4 and Compute Modules—has emerged as a versatile platform for industrial IoT (IIoT), edge computing, and smart automation. This review aims to comprehensively survey academic and industrial research where Raspberry Pi devices, irrespective of version or memory specification, have been integrated into Industry 4.0 applications, with a focus on domains such as digital twin development, SCADA integration, MQTT-based industrial communication, and predictive maintenance. Special emphasis is placed on the Raspberry Pi's role in enabling real-time data acquisition, sensor fusion, and cloud-edge interoperability within industrial environments. Furthermore, the review discusses the implications of Raspberry Pi deployments in the broader context of the transition to Industry 5.0, where human-centric and sustainable practices are becoming central. Through critical analysis of existing literature and implementations, this paper highlights current trends, identifies research gaps, and outlines future directions for deploying Raspberry Pi platforms as enablers of smart, connected, and adaptive manufacturing systems.