Design and Implementation of a Low-Cost, High-Density IIoT Gateway for Smart Factory Monitoring Using ESP32

Devya; Shib Sankar Das

doi:10.69968/ijisem.2026v5i2364-375

Authors

Devya Department of Automation and Robotics Engineering, Prestige Institute of Engineering Management and Research, Indore, India divyaaprajapati04@gmail.com
Shib Sankar Das Department of Computer Science and Engineering, Techno Bengal Institute of Technology, Kolkata , India shibsankardas721@gmail.com

DOI:

https://doi.org/10.69968/ijisem.2026v5i2364-375

Keywords:

Industry 4.0, IIoT Gateway, ESP32, Embedded Firmware, High-Density Monitoring, Resource-Constrained Microcontrollers, Chunked Transfer Encoding, Network Resilience, Data Persistence, Smart Factory

Abstract

Affordable real-time machine monitoring remains an unsolved operational challenge for small and medium-scale enterprises (MSMEs), where the capital cost of Programmable Logic Controllers (PLCs) and proprietary industrial gateways renders factory-floor visibility economically inaccessible. This paper presents a low-cost IIoT edge gateway engineered on the ESP32 microcontroller, delivering production-grade machine monitoring without the financial burden of conventional infrastructure.

The central contribution is a firmware architecture that scales a single ESP32 — equipped with only 320 KB of Static RAM (SRAM) — to simultaneously monitor and control 512 independent machine nodes (M1–M512) through a live web dashboard. This was achieved through an optimized memory-mapping strategy combined with a purpose-built Chunked Transfer Encoding mechanism over a native HTTP server, which streams dashboard payloads in bounded segments rather than constructing full responses in memory, preventing heap exhaustion under high-density node loads.

Operational continuity in electromagnetically harsh factory environments is maintained by a "Hybrid Scan & Auto-Connect" firmware routine that periodically evaluates Received Signal Strength Indication (RSSI) across a prioritized list of saved network credentials and autonomously switches to the strongest available connection, eliminating monitoring gaps caused by localized interference or access-point failures. Machine states and user-defined node labels are committed to persistent flash storage via the ESP32's Non-Volatile Storage (NVS) Preferences library, ensuring complete context restoration following abrupt power interruptions.

The proposed system demonstrates that resource-constrained microcontrollers, when paired with thoughtfully optimized firmware strategies, are fully capable of sustaining the monitoring demands of industrial-scale deployments. By eliminating dependence on expensive proprietary hardware, this gateway offers MSMEs a practical, scalable, and immediately deployable foundation for real-time factory-floor visibility within Industry 4.0 environments.

References

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