Chainlink External Adapters are designed to integrate IoT data securely and reliably into smart contracts, enabling a wide range of applications such as supply chain management and insurance claims. The Open Library Project, a winner in the Chainlink Virtual Hackathon, demonstrates how developers Aram Moghaddassi and Aaron Wasserman utilized these adapters to connect an Arduino RFID to a Chainlink oracle for a decentralized book check-out and tracking system. The tutorial provided by Moghaddassi guides developers through the process of integrating RFID data into blockchain using Chainlink nodes, emphasizing the potential of IoT devices and smart contracts to enhance efficiencies in various sectors. The article outlines the technical design, applications, and future integrations of such systems, encouraging developers to build their own hardware external adapters and explore creative uses for this technology, highlighting the importance of robust machine-to-machine communication and tamperproof data feeds in blockchain applications.