Web Configuration System for Embedded Devices

Simón Aulet · ESP32 · WiFi · Captive Portal · Embedded Systems

Persistent configuration system based on ESP32 that replaces limited physical interfaces (LCD + buttons) with a captive portal web served directly from the microcontroller.

ESP32 WiFi Captive Portal ESP-IDF Embedded Systems Web Server
Simplified usage flow of the configurator

Figure 1: Complete usage flow. The user connects to the ESP32's WiFi network, is automatically redirected to the web portal where they view and modify configuration. Changes are stored in non-volatile memory (NVS) and persist after reboots, applying directly to the machine's hardware.


Technical Specifications

Component Technology / Specification
Microcontroller ESP32-WROOM (Xtensa Dual-Core)
Network Mode Access Point (AP) with Captive Portal
Protocols HTTP (Web Server), DNS Hijacking
Persistence Non-Volatile Storage (NVS) from ESP-IDF
Framework ESP-IDF v5.4.1
Interface HTML/CSS/JS served from flash

Implementation and Validation

Web interface of the captive portal

Figure 2: Web interface served from the ESP32. Allows testing configurations temporarily and saving them persistently in NVS.

Smartphone connected to the configurator

Figure 3: Physical test with smartphone connected to the portal. Automatic redirection (captive portal) works on real devices.

Prototype with configuration 1

Figure 4: Physical configuration 1 applied. LEDs represent GPIO output states mapped to specific functions.

Prototype with configuration 2

Figure 5: Physical configuration 2 applied. Changes made from the web are immediately reflected in the hardware.


System Value

This system demonstrates that a robust, professional web configuration solution is achievable with minimal hardware and reduced cost. Using only one ESP32, without external components, keeps the implementation simple and economical while delivering full functionality.

Development was accelerated by starting from the official ESP-IDF captive_portal template, upon which configuration and persistence abstraction layers were built. This allowed focusing effort on application logic rather than designing already-proven network components.

The result is a system that works immediately upon connection, with low response times and verified configuration persistence after multiple reboot cycles. A practical solution for real deployments in technical and industrial environments.


Documentation and Source Code

Complementary material summarizing the project and detailing technical development:

Presentation Poster

Visual summary of the system, its architecture and usage flow.

Format: Interactive PDF · Content: Technical poster

Download Poster (PDF)

Technical Report

Complete document with motivation, development, implementation and project results.

Format: Interactive PDF · Content: Complete technical report

Download Report (PDF)

Project Repository

Source Code: https://github.com/SimonAulet/portfolio/tree/main/ESP32

Contains all system code: ESP-IDF firmware, web interface, build system configuration (CMake), and development scripts.