CNS Core: Small: Repurposing Smartphones to Minimize Carbon

University Of California-San Diego, La Jolla CA

Investigators

Abstract

More than a billion smartphones are sold each year and most are decommissioned less than two years later. The majority of these unwanted smartphones are neither discarded nor recycled, but languish in junk drawers and storage units. This computational stockpile represents a huge wasted potential; these smartphones have a high-performance and energy-efficient processor, extensive networking capabilities, and a reliable built-in power supply. This project gives a second life to older, discarded, idle smartphones. The research addresses key technical questions of how to transform a user-optimized, interactive device into a robust, reliable device capable of long-term, unattended operation. It develops new metrics to capture both manufacturing and operational carbon costs, couples these with economic models, and establishes a roadmap for the best opportunities for old electronic devices. Finally, the project tests these ideas at scale, to empirically establish how best to use phones-as-compute and phones-as-sensors. Repurposing smartphones to extend their lifetime is a key facet of reducing their carbon footprint. Integrated circuit manufacturing is an extremely carbon-intensive process and dominates the overall carbon cost for smartphones. Repurposing extends smartphone lifetimes to better amortize their manufacturing carbon costs. A repurposed phone can displace the manufacture of a new electronic device and lower overall carbon consumption. This project trains undergraduate and graduate students to build sustainable computing systems out of old, unwanted smartphones. This project is funded by Design for Sustainable Computing (NSF 22-060) This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.