This article provides a macro-level introduction to the communication architecture of IoT (Internet of Things) devices, helping you understand the working principles of the increasingly common IoT devices. These devices typically operate under three primary integration patterns: Direct Integration, Gateway Integration, and Cloud Integration.

1. Direct Integration Pattern

The direct integration pattern is commonly used in IoT devices such as Apple Watches and smartphones, which use Bluetooth for communication. However, Bluetooth does not provide a universal interface for device access. To overcome this, web technologies that have matured over the years are leveraged, leading to the concept of the “Web of Things.”

If a device supports HTTP and TCP/IP and can connect directly to the internet (e.g., using Wi-Fi), it follows the direct integration model. Typically, these devices require greater processing power and continuous power supply, like in smart homes. To control such devices directly via the web, you would need to implement functions like hardware control, RESTful API design, and HTTP server setup, as shown in the diagram below:

2. Gateway Integration Pattern

When devices have limited resources or cannot connect directly to the internet (e.g., they only support Bluetooth or ZigBee), they can access the web through a powerful gateway. The gateway translates various protocols into a unified external interface (e.g., converting CoAP to HTTP) and provides additional services such as security authentication, integration, temporary data storage, and device semantic description. A well-known open-source gateway project is OpenHAB, though many large vendors also offer their own proprietary gateways to support their devices.

3. Cloud Integration Pattern

The cloud integration pattern can be seen as an extension of the gateway model, where the gateway is hosted in the cloud and provides cloud services such as protocol conversion and data processing. The key advantage is that it allows for device access over the external network. Several cloud platforms support IoT, including AWS, Aliyun, and Microsoft Azure, as well as specialized platforms like Xively and Wisdom Cloud. These platforms typically use MQTT protocol and employ a structure similar to the one illustrated below. Virtual devices in the cloud store device states and management data, while a secure API Key is used for sending management commands via REST APIs.

4. Summary

The cloud-based mode often results in slower command transmission. Consequently, IoT devices may support multiple operation modes simultaneously. By utilizing the web for device control, you can easily integrate third-party automation platforms such as IFTTT to create automatic workflows and interact with popular apps like Twitter.

If you have any questions about PCBs or PCBA, feel free to contact me at info@wellcircuits.com.