This Master thesis is about research and conceptualization of a digital communication system to enrich expression and interpretation of emotions through sensor technologies in a more humane way. The project has explored and discovered user needs and concerns in digital communication through academic research, preliminary user research. For the defined target user and context, a new digital communication system, which involves meaningful tangible interactions with sensor technologies to help people express and interpret daily emotions was achieved as the result through co-creation, two rounds of user tests. In its first stage of implementation, the DUO system consists of two components, the physical interactive product as an extension of a mobile phone to translate body actions into dynamic visualizations, and the mobile application that serve as an universal tool which can be accessed both by users who have possession of the physical product and users without the product, who are willing to keep track of others’ emotions.