OT / IoT / Security by Design 21.02.2026 ⏱ 4 min read
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Stacja pogodowa ESP32 Nextion HMI OT IoT

Weather Station

ESP32 + Nextion 3.5” HMI – network integration and a security-focused approach in OT/IoT systems.

In my spare time I built my own OT / IoT weather station based on ESP32 and a Nextion 3.5” operator panel. I treat this project as a testing ground for experimenting with IoT system integration, HMI interface design, and implementing security best practices commonly used in OT environments.

Project scope

  • ESP32 as the main system controller
  • Nextion 3.5” HMI – dedicated operator interface
  • Weather and environmental data visualization
  • Password-protected access to advanced settings
  • Network integration and remote access to data
  • 3D printed enclosure, custom assembly and soldering

OT / IoT Security

  • Segmentation of access to the system interface
  • Device and configuration hardening
  • Control of exposed system interfaces
  • Protection of configuration and system parameters
  • Basic resilience against common IoT attack vectors

Lessons learned from the project

Building my own weather station was both an interesting challenge and a valuable learning experience. Most of the time was spent designing a clear and intuitive graphical HMI interface that allows real-time monitoring of environmental parameters.

HMI (Human–Machine Interface) is one of the key components of OT systems. Through this interface, operators supervise technological processes and make operational decisions.

A poorly designed or improperly secured HMI can pose a serious threat to system stability. Granting excessive privileges to users or lacking proper access control mechanisms may lead to unauthorized changes to process parameters.

In industrial environments such a situation may result in system failure, interruption of the technological process, or even a prolonged production outage.

That is why even in laboratory or hobby projects it is worth applying good practices known from OT systems: access segmentation, the principle of least privilege, and configuration change monitoring.

Next development stage

In the next stages I plan to conduct penetration testing and further system hardening. The project will also be used to simulate attack scenarios targeting the OT/IoT layer and to analyze potential threat vectors in industrial environments.