TWIN-NODE is a two-node, ultra-low-power water level monitoring system engineered for overhead tanks and outdoor environments. It operates entirely offline using ESP-NOW communication, eliminating internet dependency while ensuring reliable, low-latency data transfer between nodes. The system is designed with real-world deployment in mind, emphasizing energy efficiency, robustness, and ease of manufacturing.

The outdoor sensor node measures water level using a waterproof ultrasonic sensor and transmits data wirelessly to an indoor display node. The hardware design focuses on deep-sleep operation, GPIO-controlled power domains, and efficient voltage regulation to maximize battery life in solar-powered conditions. Component selection, PCB layout, and enclosure considerations are optimized for long-term outdoor reliability.

With versioned hardware revisions, the repository documents a clear engineering progression from a stable baseline to an improved, more manufacturable design. Complete fabrication files, schematics, 3D models, and validation reports are included, making the project suitable for learning, prototyping, and scaling toward practical IoT water management solutions.