What’s the project about?

This project is a four-layer Industrial IoT Gateway designed for modern automation and monitoring environments. It integrates LoRa, GSM, WiFi, Ethernet, RS485, RS232, SPI, I²C, relay outputs, and opto-isolated inputs into a single compact hardware platform. The gateway functions as the central controller for long-range LoRa nodes, industrial field devices, and cloud-connected systems, creating a complete and scalable industrial communication solution.

The design applies advanced PCB engineering, including RF antenna impedance matching, controlled USB 90-ohm differential routing, and a multi-stage power system engineered for stability and noise immunity in industrial environments.

Why was it created?

Industrial installations typically require multiple communication protocols and wired or wireless standards. Using separate modules for each interface increases cost, space, and maintenance complexity.

This gateway was developed to consolidate all major industrial communication interfaces into a single board and to offer a cost-effective and open-source alternative to commercial industrial gateways.

It also serves as a platform to demonstrate advanced PCB design competencies such as four-layer controlled impedance layout, RF matching for LoRa, precision USB differential routing, high-current relay design, opto-isolation techniques, and proper ground-plane management for EMC performance.

This project is my entry for the PCBWay 8th Design Contest to showcase industrial-grade embedded hardware design expertise.

How does it work?

LoRa end devices transmit long-range sensor and control data to the gateway’s LoRa module. Industrial field equipment such as Modbus sensors and meters connect through RS485, RS232, or opto-isolated digital inputs.

The ESP32 module functions as the main processor, handling data acquisition, protocol conversion, device control, and system logic.

After collecting data, the gateway communicates with local or remote servers through Ethernet, WiFi, GSM, or LoRa uplink, depending on the installation environment. The relay outputs allow automation tasks such as switching motors, valves, pumps, and alarms.

Engineering highlights

The gateway is built on a four-layer PCB with controlled impedance traces and a dedicated ground plane. The LoRa RF section includes a carefully calculated antenna matching network to ensure optimal range and efficiency. The USB interface uses a properly length-matched 90-ohm differential pair to meet signal-integrity requirements.

The power section uses high-efficiency DC-DC converters, EMI filters, and protective elements such as reverse-polarity and surge protection, with separate power domains for noise-sensitive blocks. Opto-isolated inputs ensure safety and noise immunity.

Relay outputs include flyback protection and are spaced according to safety standards. RS485 and RS232 interfaces follow proper termination and protection guidelines. The Ethernet PHY and magnetics are implemented according to reference-design recommendations.

Ground regions for digital, RF, high-power, and relay switching sections are separated to maintain signal integrity and reduce interference.

These engineering methods result in a robust and reliable gateway suitable for real industrial deployment.