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Bench Talk for Design Engineers

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Bench Talk for Design Engineers | The Official Blog of Mouser Electronics

MQTT Protocol: The Solution for Machine-to-Machine Communications? Steve Schriber

Telemetry is a relatively old concept in the communications science world. At the beginning of the last century, sensors gained the capability to send a signal over a distance, allowing scientists to monitor machine and other activities remotely. Flash forward to recent times, when with computer processors, machines can act on data sent from sensors and other machines, hence creating machine-to-machine (M2M) communications. Today’s proliferation of Internet use for data and information communications is driving the demand for standard protocols.

The Internet of Things can take on different meanings depending on its use. For commercial and industrial purposes this concept can be divided into two spheres: Industrial Internet of Things (IIoT) and the Internet of Things (IoT). Some key differences between the two are:

  • IoT applies in many market segments, including consumer goods, agriculture, manufacturing, and healthcare, while IIoT focuses on industrial applications, such as manufacturing and energy. IIoT is a smaller subset of the greater, more general IoT.
  • IoT focuses on human consumers. IIoT aspires to access as much data as possible to fine-tune industrial processes and maximize the efficiencies of a supply chain.
  • While IoT generates a large amount of data that can improve the consumer experience, IIoT data is much more voluminous and can be much more crucial regarding process success and stakeholder safety.

The key challenge to IoT and IIoT moving forward is how to handle the huge amounts of gathered data.

What the Heck is MQTT?

That was my reaction when I first approached what turns out to be a very interesting subject. The acronym means:

  • Message: In simplest terms, MQTT involves a data source publishing a message to a “broker.” The broker then dispatches the message data to all devices that have subscribed to data tags from that exact source.
  • Queue (or queuing): Despite the word “queue” in the name, MQTT is not a queue-based protocol. Apparently, this term has remained unused throughout the legacy of generational protocols.
  • Telemetry: Key to IoT and IIoT, transmission of data is the heart of telemetry.
  • Transport: Data transmission occurs from point-to-point through a centralized hub/broker.

MQTT is a simple hub and spoke system: Sensors, applications, and devices communicate through a central broker running in a data center. Devices do not attempt to communicate between themselves, as all data passes through the broker for direction. MQTT is light regarding processing requirements and, as such, lends itself well to applications within bandwidth and latency constrained networks, like those typically found in manufacturing environments. MQTT sessions are simple and quick: Connection, authentication, communication, and termination. The simplicity and “lightweight” of the protocol lends itself to an increase in scalability as data volume grows. MQTT is ideal for large and remote networks of many simple sensors such as power transmission lines, pipelines, or fossil fuel wells.

A Large Range of Applications

Besides the capability to monitor far-flung oil pipelines and other energy transmission assets, the compact, low-bandwidth nature of MQTT lends itself to many other uses. Home automation applications including heating, ventilation, and air conditioning (HVAC), lighting, smart appliances, and security systems have adopted MQTT (Figure 1). Home gardening can get high-tech through messages sent from light, temperature, and moisture sensors that route to the proper subscribers, who in turn adjust watering procedures accordingly and automatically. Total geeks can even program an Arduino® or Raspberry Pi™ to control Christmas lights using the MQTT protocol. Medical monitors, transportation network monitoring, asset tracking, environmental compliance checks, climate data logging, and automated kiosk monitoring are all examples of MQTT in use.

Figure 1: Home automation is one of the uses for MQTT.

Wrap Up

Timely and accurate information can be useful to improve performance in the consumer (IoT) and manufacturing (IIoT) worlds. As more and more data become available for interpretation and consumption, the establishment of protocols and methodologies for information sharing will be essential. In the world of M2M communications, MQTT is establishing itself as a leading protocol because it provides an increase in scalability while minimizing the effect of long latency, low bandwidth, and transmission interruptions that are prevalent in the physical manufacturing space.

Mouser Electronics can help you find the sensors, antennas, modems, data loggers, embedded processors, and many more of the components and equipment required for a robust M2M and IIoT system. A broad selection of these and other pertinent products are on the Mouser website along with technical and supportive data to aid in design and purchase decisions. Mouser offers an entire suite of informative products and resources that aim to help in the research and discovery of various topics, including IoT and IIoT.

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