Prototyping IIoT Edge Devices: A Practical Guide

Industrial Internet of Things (IIoT) unlocks unprecedented visibility into manufacturing processes, driving smarter decision‑making and higher efficiency. Enterprise‑grade IIoT solutions rely on multi‑layered architectures that safely gather data from diverse sensors, transmit it to the cloud, and analyze it to surface actionable insights. In Industrial Internet Application Development, the authors dive deep into IIoT architecture and outline strategies to meet these demanding requirements.

Excerpt from Chapter 3 of the book, this section explains how developers can build prototype devices capable of collecting and communicating data to higher‑level applications. The content is divided into the following installments:

• Prototyping devices

• Implementing HTTP connectivity

• Using WebSockets

• Using Modbus

• Using OPC UA protocols

Adapted from Industrial Internet Application Development, by Alena Traukina, Jayant Thomas, Prashant Tyagi, Kishore Reddipalli.

Chapter 3. IIoT Edge Development
By Alena Traukina, Jayant Thomas, Prashant Tyagi, Kishore Reddipalli

This chapter guides beginners through end‑to‑end prototyping: selecting the right hardware, assembling four sample devices, deploying basic IoT applications, and leveraging Predix services to store, analyze, and merge sensor data.

In this chapter, you will learn about the following topics:

• Choosing hardware for prototyping

• The Open Systems Interconnection model and its layers

• Application‑layer protocols—HTTP and WebSocket

• Industrial M2M protocols—Modbus and OPC UA

• Assembling a device for a prototype

• Preparing an SD card for a prototype

• Building and running simple IoT apps using the HTTP, WebSocket, Modbus, and OPC UA protocols

• Data management services in Predix

Hardware for prototypes

This section reviews the wide array of hardware options available for prototyping and offers guidance on selecting the appropriate board and communication protocol to ensure seamless integration among components.

Variety and cost

Open‑source boards such as Arduino, Raspberry Pi, Orange Pi, LinkIt, BeagleBone, and Tessel are all affordable. For example, an Orange Pi can be purchased for just $33, while a starter kit that includes sensors, a small display, LEDs, cables, and a breadboard typically costs around $70. Individual sensors start at $1.

Modifications

The most popular boards—Arduino and Raspberry Pi—have a range of variants. If you need Wi‑Fi, Bluetooth, USB, HDMI, or higher processing power, compare the available options to find a board that meets your exact specifications.

Comparing options

All boards are compact—roughly 8 cm wide, 5 cm high, and 2 cm thick (without a case). More powerful hardware such as the Intel NUC measures 35 × 25 × 4 cm. Connectivity is a key differentiator; many boards lack built‑in Wi‑Fi or Bluetooth, and features like GSM, GPS, cameras, or FM modules usually require separate modules.

Another critical factor is the number of sensor connectors. Assess the sensors you need and verify compatibility with the chosen board. Additional expansion boards can extend the pin count if required.

Supported sensors

Board connectors may support only analog or only digital sensors. Digital sensors emit discrete signals—e.g., the DHT11 temperature sensor outputs an integer between 0 °C and 50 °C. Analog sensors produce continuous signals, allowing values such as 11.9 °C with the TMP36 sensor, which measures from –50 °C to 125 °C. Converting between signal types is possible but adds complexity and extra components.