Easily Add Battery-free Wireless Sensors to Everyday Objects: System Implementation and Usability Study

Abstract

The trend of IoT brings more and more connected smart devices into our daily lives, which can enable a ubiquitous sensing and interaction experience. However, augmenting many everyday objects with sensing abilities is not easy. BitID is an unobtrusive, low-cost, training-free, and easy-to-use technique that enables users to add sensing abilities to everyday objects in a DIY manner. A BitID sensor can be easily made from a UHF RFID tag and deployed on an object so that the tag’s readability (whether the tag is identified by RFID readers) is mapped to binary states of the object (e.g., whether a door is open or closed). To further validate BitID’s sensing performance, we use a robotic arm to press BitID buttons repetitively and swipe on BitID sliders. The average press recognition F1-score is 98.9% and the swipe recognition F1-score is 96.7%. To evaluate BitID’s usability, we implement a prototype system that supports BitID sensor registration, semantic definition, status display, and real-time state and event detection. Using the system, users configured and deployed a BitID sensor with an average time duration of 4.9 minutes. 23 of the 24 users deployed BitID sensors worked accurately and robustly. In addition to the previously proposed ‘short’ BitID sensor, we propose new ‘open’ BitID sensors which show similar performance as ‘short’ sensors.