**3. System Description**

The user interface of our system consists of simple smart devices with embedded screens and visual LED cues that provide important information to the users in the right place at the right time. The idea behind these smart devices is that they are normal objects such as fridge magnets or cabinet drawer hooks that also have the capability of delivering information. The system has some key functions including: storing and processing data from the users, generating notifications and dispatching them to the properly smart device(s).

The two prototypes described in this paper were designed and built following a conceptual framework for smart device-based notifications [9]. This framework proposes a modular conception of the system and defines guidelines for the decisions during the design process. The following sections describe the main components of the system.

Many of the design decisions of the two devices described in this paper are the result of lessons learned through the construction of several smart devices (included in the conceptual framework). One of the most important characteristics is the use of visual cues. Even though sound cues (auditory notifications) were strongly suggested by developers during the design process, the use of the framework lead to the decision of avoiding such notifications. The main reason to avoid sound notifications is that this type

of notifications can easily become overwhelming. Moreover, visual recognition memory is superior to auditory recognition memory [22]. Furthermore, encoding messages in sounds is a difficult task; therefore, auditory notifications would have to present the full text of the notification to be effective.
