RAFU: Cold Chain Environmental Monitoring Solution

RAFU is an advanced IoT-based cold chain monitoring solution engineered for reliable environmental monitoring in both connected and remote deployment environments. The system combines Bluetooth Low Energy (BLE) sensing technology with a hybrid GSM and Wi-Fi gateway architecture to provide continuous monitoring of temperature, humidity, device battery status, and geolocation data across distributed sensing points. Designed around an ESP32 embedded platform with Quectel cellular communication, the RAFU device enables resilient telemetry acquisition and cloud synchronization for cold chain applications requiring real-time monitoring and historical environmental analysis.

The system architecture consists of a central RAFU gateway device and up to four BLE temperature and humidity sensors deployed in different physical locations such as refrigerators, offices, cold rooms, or storage facilities. The main gateway periodically scans and acquires sensor telemetry over BLE before securely publishing the data to the cloud platform using GSM or Wi-Fi connectivity. The device integrates GPS functionality for deployment tracking, battery monitoring for power management, and intelligent alert systems using a WS2812 smart LED and PWM buzzer for user feedback, heartbeat indication, charging status, and operational alerts. The firmware was developed using ESP-IDF with a robust event-driven architecture optimized for low-power operation and reliable long-term deployment.

From an engineering and deployment perspective, the RAFU project involved embedded systems firmware development, hardware productization, BLE integration, GSM telemetry systems, cloud dashboard integration, enclosure integration, field deployment workflows, and end-user installation support. The solution supports both USB-C and solar-powered charging configurations through an MPPT charging subsystem operating within a 3.5V to 18V input range. The project progressed from prototype validation to packaged deployment-ready systems with real-time dashboards, automated environmental monitoring, and scalable remote cold chain infrastructure suitable for logistics, healthcare, food storage, and industrial refrigeration applications.