Aqua Monitor: A Decoupled LoRa-to-Cloud IoT Architecture for Low-Cost Multi-Pond Water Quality Monitoring

The significant research contribution is the development of Aqua Monitor, a low-cost, Wi-Fi-independent multi-pond water-quality monitoring architecture that combines point-to-point 433 MHz LoRa communication, edge-side MAD/IIR signal filtering, physics-informed DO estimation, and a dual Firebase (Realtime Database + Firestore) cloud architecture. The system enables real-time and historical monitoring of multiple ponds at a hardware cost of approximately 9,550 BDT (USD 77.64).