Tsvetan Usunov, founder of Bulgarian open-source hardware company Olimex, has demonstrated a new application for the company's ESP32-POE development board by transforming it into a compact Wi-Fi NAT gateway. The project enables users to share a wired Ethernet connection over Wi-Fi using a single Power-over-Ethernet (PoE) cable for both power and network connectivity, offering an inexpensive solution for remote deployments and industrial networking applications.
The project is based on the Olimex ESP32-POE and ESP32-POE-ISO development boards, which combine Espressif's ESP32-WROOM-32 module with a Fast Ethernet interface and IEEE 802.3-compliant PoE support. Unlike traditional wireless routers, the device operates as a Network Address Translation (NAT) gateway, creating its own isolated Wi-Fi network with DHCP services while routing traffic through the primary wired network connection.
Olimex ESP32-POE Specifications
Wireless & Networking
- ESP32-WROOM-32 module
- Integrated 2.4GHz Wi-Fi 802.11 b/g/n
- Fast Ethernet interface
- NAT routing support
- DHCP server functionality
- Wired Ethernet uplink with Wi-Fi client access
Processor
- Dual-core Tensilica Xtensa processor
- Clock speed up to 240MHz
Power
- IEEE 802.3 Power-over-Ethernet (PoE) support
- Single-cable power and networking
- Compatible with PoE switches and injectors
Available Variants
- ESP32-POE
- ESP32-POE-ISO with galvanic isolation
Software
- Arduino IDE compatible
- Open-source firmware
- GNU GPL v3 licensed software
The key advantage of the design is its simplicity. By utilizing PoE, only a single Ethernet cable is required to provide both power and network connectivity, making it suitable for installations where power outlets are unavailable or difficult to access. This can include industrial monitoring systems, remote sensors, surveillance installations, smart building deployments, and temporary networking setups.
NAT Gateway Performance
While the ESP32 was not originally designed as a networking gateway processor, Usunov's implementation delivers practical performance for lightweight networking applications. Testing showed throughput reaching approximately 4.8 Mbps, which is sufficient for telemetry, IoT devices, remote monitoring systems, and basic internet connectivity. However, it is not intended to compete with dedicated Wi-Fi routers or enterprise access points.
The gateway creates a separate local network for connected Wi-Fi devices, assigning IP addresses through its built-in DHCP server. Traffic is then translated and routed through the Ethernet connection using NAT, allowing wireless devices to access the internet or resources on the upstream network without requiring direct integration into the primary LAN.
Open-Source Hardware and Software
One of the most attractive aspects of the project is its fully open-source nature. The gateway firmware is available on GitHub under the GNU General Public License v3, while the hardware design files for the ESP32-POE boards are released under the Apache 2.0 license. This allows developers to customize, modify, and integrate the solution into their own projects without vendor lock-in.
The software can be compiled and uploaded using the familiar Arduino IDE environment, making it accessible to hobbyists, makers, and professional developers alike. Both ESP32-POE and ESP32-POE-ISO boards are supported by the firmware.
Potential Applications
The ESP32-POE Wi-Fi gateway can be useful in a variety of scenarios:
- Industrial IoT deployments
- Remote sensor installations
- Smart building automation
- Temporary Wi-Fi hotspots
- Network extension in PoE-enabled environments
- Low-power edge networking projects
- Embedded networking appliances
Its combination of low cost, small size, and single-cable deployment makes it particularly attractive for embedded and industrial applications where conventional networking equipment may be oversized or too expensive.
The Olimex ESP32-POE and ESP32-POE-ISO development boards are available through the Olimex store, with pricing starting at approximately €17.95 before volume discounts. The complete project, including source code and documentation, is available through Olimex's open-source repositories.
Although throughput is modest compared to dedicated networking hardware, the project demonstrates how a low-cost ESP32 development board can be repurposed into a practical Wi-Fi gateway solution. For developers seeking a compact, PoE-powered networking bridge for IoT and industrial applications, the ESP32-POE NAT gateway offers an interesting open-source alternative to traditional routers and access points.
.jpeg)
.jpg)
0 Comments