Ambient computing is one of the more significant recent advances in computer-human interactions. With the ambient intelligence paradigm, computers become embedded in our natural surroundings. As they are context sensitive and adaptable, they better provide smart services to humans. But ambient computing requires communication between several heterogeneous components that are not supposed to communicate each other. This paper describes how we use a workflow to facilitate the design of multichannel interfaces for ambient computing. Our results show that different devices (such as Wiimote, multi-touch screen, telephone, etc.) can be managed in order to activate real things (such as lamp, fan, robot, webcam, etc.). A smart digital home case study illustrates a possible implementation of our approach and shows how it allows redesigning easily some parts of the ambient system just by modifying the workflow.