In this paper, we present the design case for Gate Reminder, a family shared home appliance located at the front door area that represents informative messages, reminding users of things they need to take and know before leaving home. For this project, we built a working prototype and conducted a number of usability and user experience evaluations. In the paper we describe (1) why we chose reminder as our research topic (2) what we found from the early phases of user research for the Gate Reminder (3) what design requirements and decisions we have established from our user study (4) how we designed the working prototype based on our design decisions and (5) what we have learned from our user experience evaluation. The requirements for effective reminding, the usability challenges in ubicomp application, issues in the current prototype and future developments will be presented throughout the paper as well.