Industrial process automation systems are adopting event based communication. Pushing control loops towards low-level devices implies a need for lightweight embedded devices that are able to recognize and to react to events. Atomic events however, such as a value read by an individual sensor exceeding certain value, do not separately suffice to capture scenarios where a reaction should occur to a sequence of low-level events matching certain pattern, rather than to a single atomic event. Therefore, it becomes desirable that resource-constrained low-level devices are equipped with some, possibly lightweight, form of event filtering and processing. In this paper we propose to implement a lightweight complex event processing using the concurrent reactive objects (CRO) model. A core feature of the CRO model is its s ability to react to atomic events. Between the reactions, which basically are function executions, the system remains idle, and thus does not occupy the CPU and is energy-efficient. Additionally, CRO models can be executed in an efficient and predictable manner onto resource constrained platforms and offers low-overhead real-time scheduling through exploiting underlying interrupt hardware according to given time constraints.
