Types of Edge Devices: From Sensors to Industrial Gateways

"Edge Device" is a catch-all term that covers everything from a Fitbit to a rack-mounted server. This ambiguity leads to confusion in project planning. This guide categorizes the hardware ecosystem into three distinct tiers: The Far Edge (Sensors), The Industrial Edge (Gateways), and The Infrastructure Edge (Servers). We explain the "Thin Edge vs. Thick Edge" concept, helping you understand which type of edge device is required for tasks ranging from simple temperature monitoring to complex real-time AI video analytics.

If you ask three engineers to define an edge device, you will get three different answers.

One will show you a temperature probe. Another will show you a 5G router. The third will show you a mini-server.

They are all correct.

The term edge device describes where the hardware sits (at the edge of the network), not what it does. However, treating a simple sensor the same as a powerful gateway is a recipe for disaster in network planning.

To build a scalable architecture, we must categorize these devices based on their computing power and responsibility. We divide the world of the edge device into three distinct tiers.

Also known as the Thin Edge.

These are the devices that touch the physical world. They are the eyes, ears, and hands of the network.

Characteristics:

• Brain: Microcontroller (MCU). Very low processing power.
• OS: often "Bare Metal" or FreeRTOS. No Linux.
• Power: Battery or coin cell.
• Function: Generate data.

Examples:

• A Bluetooth vibration sensor on a motor.
• A smart light bulb.
• A GPS tracker on a shipping container.

Is a sensor really an edge device? Technically, yes. But in modern architecture, they are often considered "End Nodes." They don't usually process data; they just report it. They rely on a more powerful upstream device to make sense of the noise.

Also known as the Intelligent Edge.

This is the most critical layer for Enterprise and Industrial IoT (IIoT). This hardware sits between the sensors and the cloud.

Characteristics:

• Brain: Microprocessor (CPU like ARM Cortex-A).
• OS: Linux-based (e.g., RobustOS, Ubuntu Core).
• Connectivity: 4G/5G, Wi-Fi, Ethernet, Serial (RS232/485).
• Function: Aggregate, Translate, Filter, and Secure.

Examples:

• Industrial IoT Gateway: Connects to 50 sensors, converts Modbus to MQTT, and filters out normal readings.
• Cellular Router: Provides 5G backhaul for a remote site and runs a firewall.

This type of edge device is the workhorse. It has enough power to run local applications (via Docker containers) and enough intelligence to secure the network, yet it is low-power enough to run on solar.

Also known as the Thick Edge or Heavy Edge.

When you need to process massive amounts of data that a small gateway cannot handle, you bring in the heavy artillery. These are essentially data center servers shrunken down and placed on-site.

Characteristics:

• Brain: Server-grade x86 CPUs (Intel/AMD) and often GPUs (NVIDIA).
• Power: Mains power required (100W+).
• Function: Heavy computation, AI training, Video rendering.

Examples:

• A MEC (Multi-access Edge Computing) server at a 5G cell tower.
• A ruggedized server rack in a factory closet analyzing 20 streams of 4K video for safety compliance.

While powerful, this type of edge device is expensive and requires climate-controlled environments, making it unsuitable for harsh outdoor deployments.

Most successful IoT projects use a combination. You deploy hundreds of "Thin" sensors, connected to dozens of "Industrial" gateways. You rarely need a "Thick" edge device unless you are doing heavy AI video processing.

Don't look for a single "best" device. Look for the right team.

A sensor is useless without a gateway to connect it. A gateway is useless without sensors to feed it data.

Understanding these three tiers prevents over-engineering. You don't need a $5,000 server to monitor a water pump, and you can't use a $20 sensor to run a firewall. By selecting the correct class of edge device for each layer of your network, you balance cost, performance, and complexity effectively.