Low-cost modular IoT gateway with LLM-assisted design-time firmware generation

Abstract

The adoption of Internet of Things (IoT) technologies is often constrained by challenges related to interoperability, diverse use cases, and the lack of standardization across devices and protocols. These barriers are particularly evident during the prototyping and development of novel IoT systems, where accessible and cost-effective tools are needed. This work introduces an “Affordable Modular IoT Gateway”, a flexible and extensible solution built on Arduino-compatible hardware to support the integration of wireless sensors, communication technologies, and cloud platforms. The gateway architecture separates sensor-side acquisition and endpoint-side forwarding into interchangeable modules connected through a JSON-over-I2C internal interface. This work also introduces an LLM-assisted design-time programming workflow for generating Arduino-compatible firmware templates for the proposed modular gateway architecture. The tool is used during design-time firmware development, where generated firmware templates are reviewed, compiled, tested, and deployed to the gateway modules using the standard Arduino development workflow. The gateway was evaluated with environmental sensors measuring parameters such as vibration, temperature, and humidity, using Bluetooth, Wi-Fi, and LoRaWAN for communication. Connections to cloud-based services via Wi-Fi and LoRaWAN demonstrated the feasibility of the architecture in selected wireless scenarios. The results indicate that the proposed gateway can support low- and moderate-rate IoT data acquisition in research and prototyping contexts where flexibility, affordability, and ease of modification are important. The work highlights the role of modular low-cost hardware, shared internal communication interfaces, and design-time firmware generation in making IoT system development more accessible.