Building Industrial IoT Gateway with Raspberry Pi

Introduction

An Industrial IoT (IIoT) Gateway is the bridge between factory devices and the cloud platform. In this article, we will build a gateway using a Raspberry Pi.

Hardware Requirements

Raspberry Pi 4 (4GB+ recommended)
RS-485 HAT for Modbus RTU
Digital I/O HAT
UPS HAT (for power backup)
Industrial case

Software Stack

Base System

# Install Raspberry Pi OS Lite (64-bit)
# Then install Docker
curl -fsSL https://get.docker.com -o get-docker.sh
sudo sh get-docker.sh

Docker Compose Stack

version: '3.8'
services:
  # MQTT Broker
  mosquitto:
    image: eclipse-mosquitto:2
    volumes:
      - ./mosquitto:/mosquitto/config
    ports:
      - "1883:1883"

  # Node-RED for flow programming
  nodered:
    image: nodered/node-red
    volumes:
      - ./nodered:/data
    ports:
      - "1880:1880"

  # Telegraf for metrics collection
  telegraf:
    image: telegraf
    volumes:
      - ./telegraf:/etc/telegraf
    privileged: true

Modbus RTU Integration

// Node-RED function node
const ModbusRTU = require("modbus-serial");
const client = new ModbusRTU();

// Connect to Modbus device
await client.connectRTUBuffered("/dev/ttyAMA0", {
  baudRate: 9600,
  parity: "none"
});

// Read holding registers
const data = await client.readHoldingRegisters(1, 0, 10);
msg.payload = data.data;
return msg;

Edge Computing with Node-RED

[
  {
    "id": "temperature_alert",
    "type": "function",
    "func": "if (msg.payload.temp > 80) {\n  msg.alert = 'HIGH_TEMP';\n}\nreturn msg;"
  }
]

Conclusion

Building an Industrial IoT Gateway with a Raspberry Pi is a cost-effective and flexible choice that can be customized to suit the needs of any factory.