Smart Objects and the Internet of Things provide unparalleled means toconnect the physical world with the digital world, enabling importantapplications such as Smart Infrastructures, Smart Cities, and SmartToys. But existing systems are typically proprietary and tailored toone specific application and sacrifice interoperability for low powerconsumption. This hinders widespread adoption.CALIPSO builds Internet Protocol (IP) connected smart objectnetworks, but with novel methods to attain very low power consumption,thereby providing both interoperability and longlifetimes. CALIPSO leans on the significant body of work on sensornetworks to integrate radio duty cycling and data-centric mechanismsinto the IPv6 stack, something that existing work has not previouslydone. CALIPSO works at three layers: the network, the routing, andthe application layer. We also revisit architectural decisions onnaming, identification, and the use of middle-boxes.We are not alone in seeing the vision of IP-based smart objects, asevidenced by the IPSO Alliance, IETF standards (6LoWPAN, ROLL, CoAP), andrecent start-ups.CALIPSO works within the IETF/IPv6 framework, which includes therecent IETF RPL and CoAP protocols. This gives a structure forevaluation that has not previously been available. We use Contikiopen source OS, Europe's leading smart object OS, as the targetdevelopment environment for prototyping and experimental evaluation.We use three applications to drive our work: Smart Infrastructures,Smart Cities, and Smart Toys, all of which need both standardizedinterfaces and extremely low power operation. We see experimentalvalidation and evaluation as critical to the success of the project.We expect CALIPSO results to impact four areas: standards,open source software, scientific research, and commercial products.Project partners have extensive experience in the application domains,the IETF, sensor networks, and open source software.