In this article we show a way to model and verify programs running on LEGO RCX bricks using the tool UPPAAL. We are able to model two RCX units communicating through an infrared channel. To facilitate the distribution of programs on the two RCXes, we develop the "IR Protocol", which allows both RCXes to read and write variables and I/O ports on the other RCX. The protocol makes use of a simplified version of Fischer's mutual exclusion protocol. Both the behavior of Fischer's protocol and the IR Protocol are verified. It turns out that we have to restrict our models in order to verify anything but very simple programs. A simplified model is shown, and measured to be faster. The IR protocol is demonstrated in a LEGO test setting, and we discuss how to distribute the program controlling it. 1 Introduction The theme of this article is automatic verification of realtime systems using UPPAAL. UPPAAL is a tool box for modeling, simulation, and verification of real-time systems modeled as ti...

. In this paper we show that every real-time system specified in a certain subset of Duration Calculus [24] can be decomposed into an untimed system communicating with suitable timers. Both asynchronous and synchronous communication are considered. 1 Introduction Real-time systems are reactive systems where reactions to certain inputs have to occur within given time intervals [8, 16, 14, 11]. These systems usually consist of some physical process for which a suitable controller has to be constructed such that the controlled process exhibits the desired time dependent behaviour. The interaction between process and controller proceeds via sensors and actuators as shown in Fig. 1. process sensors actuators controller Fig. 1. Real-time system When constructing the controller the reaction times of all components of this system have to be taken into account. Since real-time systems are more difficult to design and verify than untimed reactive systems, methods for separating time-...