SuryaRakshak: An IoT-Enabled, Solar-Powered Spoilage Monitoring System for MSME Storage Facilities

Abstract

Spoilage of stored grain, produce and packaged goods is a persistent source of loss for micro, small and medium enterprises (MSMEs), yet most commercial cold-chain solutions are refrigeration-based and priced beyond the reach of small storage operators. This paper presents SuryaRakshak, a solar-powered retrofit monitoring kit designed to prevent spoilage in unrefrigerated MSME storage rooms rather than to refrigerate them, positioning it in the affordable, non-refrigeration tier that is underserved by players such as Inficold and Ecozen. The system pairs an STM32F401 “Black Pill” microcontroller with a Sensirion SHT31-DIS temperature-and-humidity sensor, a CN3791 MPPT solar charge regulator, and a 6000 mAh LiFePO4 backup cell to provide continuous, off-grid environmental monitoring. A SIM800L GPRS module gives the unit cellular alerting independent of Wi-Fi availability, while front-panel status LEDs and an onboard display give operators an at-a-glance read of Power, Solar, Normal, Warning and Critical states. The enclosure, standoffs and sensor housing are 3D-printed in PETG/ABS and sealed to an IP54 standard. This paper documents the objectives, literature context, problem identification, system architecture.

Introduction

The text presents SuryaRakshak, a low-cost, solar-powered monitoring system designed to reduce post-harvest and post-production spoilage in small and medium-sized enterprises (MSMEs) in India. The system targets unrefrigerated storage rooms where temperature and humidity are often not continuously monitored, allowing environmental changes to damage stored grains, spices, and packaged foods before operators notice.

Problem

Existing solutions generally fall into two categories:

• Refrigeration-based systems: These actively control temperature but require significant investment, electricity, insulation, and maintenance, making them expensive for small MSMEs.
• No monitoring: Many small storage facilities have no automated monitoring, so temperature or humidity problems may remain unnoticed until products are already damaged.

SuryaRakshak aims to fill the gap between these two options by providing early detection and alerting rather than active cooling.

Objectives

The main objectives of SuryaRakshak are to:

• Continuously monitor temperature and relative humidity.
• Operate independently of the electrical grid using solar power and battery storage.
• Alert operators about abnormal conditions through LED indicators and GSM/GPRS messaging.
• Avoid dependence on Wi-Fi or an on-site internet connection.
• Keep the system affordable for small MSMEs.
• Use a retrofit-friendly, IP54-rated enclosure that can be easily installed in existing storage rooms.

Literature review

Previous research demonstrates the effectiveness of IoT-based environmental monitoring, solar-powered sensing, and low-cost hardware for reducing food spoilage. Some systems combine monitoring with refrigeration, cloud analytics, artificial intelligence, or machine learning.

SuryaRakshak follows the general principle of continuous environmental monitoring but differs by intentionally keeping the system simple and affordable. Instead of actively cooling the storage area or using complex AI-based spoilage prediction, it uses threshold-based monitoring and alerts so operators can take corrective action before significant losses occur.

Proposed methodology

The development process follows a structured sequence:

Objectives → Literature Review → Problem Identification → Architecture Design → Component Selection → Fabrication → Wiring → System Bring-Up → Enclosure Assembly → Testing and Documentation

This approach covers both hardware and software development, including sensor integration, GSM communication, solar charging, firmware testing, enclosure construction, and system validation.

System architecture

The electrical architecture consists of five main functional groups:

1. Control Logic Board: An STM32F401 “Black Pill” microcontroller acts as the central controller.
2. Environmental Sensor: A Sensirion SHT31-DIS measures temperature and humidity through an I²C interface.
3. Power System: A 6000 mAh LiFePO4 32700 battery provides backup power.
4. Solar Charging: A CN3791 MPPT solar charge regulator charges the battery using solar energy.
5. Communication and Display: A SIM800L GSM/GPRS module sends alerts through cellular communication, while front-panel LEDs indicate system status.

The STM32 microcontroller collects sensor readings, compares them against configured thresholds, controls the status LEDs, and communicates with the GSM module using UART and AT commands.

Overall conclusion

In summary, SuryaRakshak is designed as an affordable, autonomous early-warning system for MSME storage facilities. Its key innovation is its focus on monitoring and alerting instead of refrigeration, making it potentially more accessible to small businesses with limited budgets, unreliable electricity, and no Wi-Fi.

The combination of temperature/humidity sensing, solar power, LiFePO4 battery backup, GSM/GPRS alerts, and a simple retrofit enclosure provides a practical approach to detecting storage conditions that could lead to spoilage. The system is therefore positioned as a low-cost alternative between expensive refrigeration systems and the absence of monitoring altogether.

Conclusion

1) SuryaRakshak targets the affordable, non-refrigeration tier of MSME storage monitoring that is presently underserved by refrigeration-first vendors such as Inficold and Ecozen. 2) Solar power with an LiFePO4 buffer gives the unit off-grid autonomy suited to storage rooms with unreliable electricity. 3) I²C-based temperature/humidity sensing paired with GPRS alerting provides continuous monitoring and remote notification without depending on facility Wi-Fi. 4) A 3D-printed, IP54-sealed enclosure keeps the bill of materials low (~?9,450) wh 5) ile remaining retrofit-friendly. 6) Overall, SuryaRakshak offers a low-cost, self-powered early-warning system that helps MSME operators intervene before stored goods are damaged, rather than bearing the capital cost of full refrigeration.

References

[1] A. Nanwatkar et al., “IoT Based Food Cold Storage Monitoring and Controlling System,” ResearchGate, 2024. [2] “Design of a Smart IoT-Based Control System for Remotely Managing Cold Storage Facilities,” PMC, National Center for Biotechnology Information. [3] “An AI-Integrated Renewable-Powered Cold Storage System with Advanced Environmental Sensing for Smallholder Farmers,” Engineering, Technology & Applied Science Research (ETASR), 2025. [4] “Cold Chain Monitoring with IoT Sensors: A Data-Driven Approach to Reducing Spoilage in Temperature-Sensitive Supply Chains,” British Journal of Earth Sciences Research (and related outlets), 2025. [5] “Solar-Thermoelectric Mobile Storage System Integrated with Electric Vehicles for Reducing Postharvest and Microbial Losses in Agro Produce Transportation,” Scientific Reports, 2025. [6] “An IoT Smart System for Cold Supply Chain Storage and Transportation Management,” Engineering, Technology & Applied Science Research (ETASR). [7] “Design, Development and Evaluation of Solar Powered DC Cold Box for Sustainable Supply Chain of Food and Medicine,” 2026.

Copyright

Copyright © 2026 Sarwin Krishna N, Nirmal Kumar G, Saravana Kumar M. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.