Cairn — Nanopayment Environmental Oracle

Community sensor networks generate enormous amounts of valuable data. +200k personal weather stations, +10k air quality sensors, seismic, radiation networks, run by hobbyists worldwide. Today, commercial platforms like Weather Underground and PurpleAir paywall this data while paying contributors zero. Open networks like Sensor.Community share data freely but have no sustainability model. Autonomous agents across parametric insurance, climate risk monitoring, supply chain management, automated research, and weather derivative pricing need granular, hyperlocal, real-time environmental data that neither system serves. Cairn is the payment layer that resolves both failure modes. Sensor operators register on-chain with a USDC stake and publish x402-gated reading endpoints. Autonomous customer agents discover sensors near a target location, buy verified readings per query through Circle Nanopayments, and act on the results. Operators keep 100% of their quoted rate; the Cairn aggregator charges a transparent 2% service fee for discovery, cross-reference verification, and on-chain attestation. Verification is structural. Each query selects a quorum of three sensors, compares readings via median plus median absolute deviation, and posts an immutable attestation to Arc. Operators that consistently disagree with the consensus see their reputation drop and their stake slashed automatically. The demo features a parametric weather insurance contract (one of many possible customer agents) continuously buying verified temperature readings from 5 operators around a coverage zone. The market cannot exist on any other rail. Per-query value is fractions of a cent. Stripe, L1 gas, and enterprise oracle pricing are all off by orders of magnitude. Circle Nanopayments on Arc is the only infrastructure where this market clears.