Abstract
Linking things in the physical world with related digital resources and content in the virtual world is one of the visions of ubiquitous computing. Radio frequency identification tags, more specifically NFC tags, attached to the things and places in the physical world and using personal mobile devices equipped with readers to access the services and information associated to the tags, is studied in this paper. Eight trials representing different applications are described and the results of user experiments are reported. The main design findings are as follows: the standard size of the tag may be too limiting, we should allow tags of different visual appearance, form and size; the spatial positioning of tags in the physical interaction space gives a designer a lot of freedom but may also pose the risk of inconsistent and haphazard designs; complexity of the interaction task may be divided between using menus and keys of the personal device or using multiple tags; consistent and prompt feedback is important, feedback should use suitable modalities, including haptic feedback; the service or information provided should ex-ploit location information, i.e. the place of the specific tag, and finally fallback plans for unoperational or broken tags should exist.