We propose a novel tool, called objSampler, with which users can record and recall “encounters” with objects in ubiquitous computing environments. We encounter various things, individuals, and places in the real world either consciously, meaning encounters that we are aware of, or unconsciously, meaning those we are unaware of but physically close to them. While some of those encounters are particularly important or treasurable to us, the physical memory in our brain is often too volatile to remember them. In objSampler, we address this issue by providing a state-ofart hardware called objPipette that embeds a sensor node, an RF-ID reader, and a battery cell. Users can record conscious encounters with it by scanning RF-ID tags pasted on real world objects. In addition, the objPipette detects and records the places where the user is. Users can recall the recorded encounters by using a software support in objSampler, called objScope. This paper describes the design and implementation...