Auditable Real-Time Cold-Chain Monitoring with IoT and Blockchain Anchoring

Safe vaccine storage hinges on continuous, trust-worthy temperature supervision and evidence that records have not been altered. Yet many cold rooms still rely on fragmented logging tools that lack real-time alerts, end-to-end traceability, and audit-ready data. This paper presents a practical, low-cost architecture that integrates Internet of Things (IoT) sensing with blockchain anchoring to deliver real-time monitoring and visibility, reliable anomaly detection, and tamper-evident provenance for cold-chain storage. The design couples minute-level telemetry and dashboarding with alert debouncing/hysteresis to reduce false alarms, while anchoring hourly summaries and event alerts on-chain to create a verifiable trail without exposing raw data or incurring recurring fees during experimentation. A prototype in a vaccine cold-room scenario demonstrates that the approach is simple to deploy on commodity hardware, scales by adding room-s/sensors, and produces operator-friendly notifications along-side independently verifiable records. This combination of edge retention and cryptographic anchoring provides a pragmatic path for pharmacies, clinics, and warehouses to upgrade from basic loggers to transparent, audit-ready monitoring, bridging operational needs (alerts) and compliance needs (provenance) in one system.