As we witness a surge in technological advancements, sensors and actuators increasingly integrate into our daily lives, offering diverse types and capabilities. However, in current Wireless Sensor and Actuator Networks (WSANs), there is a lack of studies on integrating WSAN devices with limited availability and accessibility. While existing research primarily addresses WSAN devices that are either already compatible, homogeneous, or involve WSAN devices requiring extensive modifications, creating collaboration between different types of sensors and actuators from varied networks is a significant challenge and remains under-explored. To address these challenges, this research first introduces a novel concept of modularity in WSAN devices. Secondly, it presents a novel design model (Ease of Access (EoA) design model) for a modular WSAN (m-WSAN) system architecture by leveraging pervasive communication and distributed system design that can integrate diverse WSAN devices. The EoA design model provides a comprehensive method for categorizing and integrating distinct WSAN devices. It also offers an innovative WSAN service model leveraged by blockchain that facilitates smooth communication and collaboration among diverse WSAN devices while providing services to users within the network. The design feasibility of such a system is validated by creating an m-WSAN system by integrating four distinct robotic systems and testing the designed network system to provide various operational services. The results demonstrate that any device can be added or removed from the m-WSAN system seamlessly without compromising the network system’s integrity. Furthermore, this study lays the foundation for designing a modular robotic system comprising various sensor and actuator modules, each contributing distinct functional capabilities to the overall robotic system. This approach benefits industrial applications by offering a flexible and scalable network for integrating diverse robotic devices, enhancing automation, and improving operational efficiency.