IoT Sensors: 5 Types and How They Work

Industrial Internet of Things (IIoT) sensors collect information from critical equipment and assets, trigger pre-set limits, and communicate data to a centralized computer system to help maintenance managers make better, smarter, and faster decisions.

According to McKinsey, the potential of saving nearly $4 trillion exists for Internet of Things-related efficiency and productivity improvements. That includes IIoT sensor equipment.

What are IIoT sensors?

IIoT sensors are small devices that attach to critical assets to collect key data. By providing 24/7 monitoring, these sensors play an important role in helping maintenance teams access real-time information. This data then helps technicians spot problems before major breakdowns occur, providing the foundation for preventive and predictive maintenance efforts.

Five types of IIoT sensors

Dozens of sensors are available today, but the five most important sensors for the maintenance professional are vibration, gas, temperature, humidity, and security sensors.

Vibration sensors

Vibration sensors measure the level of vibration on a particular piece of sensitive equipment. Most often vibration sensors are used on rotating machinery. Then, if abnormal vibration is detected, they can alert maintenance technicians of potential problems in the particular asset.

Gas sensors

If you require the presence or absence of a particular type of gas, sensors can help you monitor these levels around the clock. Carbon monoxide detectors are a popular consumer example, setting off an alarm when this poisonous gas is present. In a factory, CO, CO2, particulate matter, and H2S can all be monitored with sensors.

Temperature sensors

Whether you want to track ambient temperature around a particular piece of equipment, need a hardwired option, or require a regular probe reading, wireless temperature sensors can record and send you readings at regular intervals. They can track pre-set acceptable ranges and alert teams when assets fall out of range.

Humidity sensors

Similar to how humidity affects our human comfort levels, some equipment is also very sensitive to humidity. These sensitive assets must stay within certain humidity ranges to operate at peak efficiency. Sensors can measure relative humidity, and even grains or weight of water in the air. Automated calibration delivers absolute humidity at certain temperatures and can alert maintenance teams when readings raise or drop out of range.

Security sensors

Perhaps the well-known sensors are security-focused ones. These can detect motion and status of windows and doors (open or closed). Security sensors can also help ensure valuable assets are not stolen, and providing excellent tracking data on the location and technician assigned to shared equipment.

How IIoT sensors are changing maintenance

In the past, maintenance technicians had to physically change things like temperature, humidity, and vibration during regular examinations of critical assets. These manual checks could only be performed periodically and were subject to human error.

Sensors help address both of those shortfalls to improve maintenance practices. They provide 24/7 monitoring and automatically log data. This data can be viewed remotely, so the need for technicians to be present in data collection is eliminated. Additionally, automated sensors generate gathered data in easy-to-use dashboards. Sensors allow for higher accuracy of data, again because they automate so many processes. This reduces human error greatly and allows corresponding metrics to improve, such as availability and reliability.

How IIoT sensors work

In a very basic sense, sensors transform a physical property into an electrical signal that we can measure. Sensors monitor and react to these signals, allowing algorithms to take action when measurements are abnormal.

In an IoT or an IIoT system, many components are working together. Those components are: sensors, the cloud, data processing, and an end-user interface.


Sensors are the hardware that you attach to assets to collect data from a specific area. As we learned above, there are many different types of sensors. Some sensors can be bundled and function as one, but the first component of any IIoT system is the hardware that will collect data.

The cloud

"The cloud" is an interconnected network of servers that collect and store information for people and businesses. In an IIoT system, the sensors connect to the cloud - usually through WiFi, cellular, or Bluetooth networks. Choosing the right way for your sensors to connect is important, but it is most important that they just get the data to the cloud.

Data processing

Once it's in the cloud, softwares or algorithms process the data. Sometimes, these analyses are simple, such as only checking that the reading is in the normal range. Other times, the processing is much more complicated than that.

End-user interface

The processed data finally must be made accessible to the end-user. The information  is often communicated to users as alerts from a software. These can come in the form of in-app notifications, emails, text messages, and so on.

Some actions occur automatically. If a temperature records outside of the normal range, your system may automatically adjust the thermostat to compensate for the issue.

Three benefits of IIoT sensors

As sensor technology advances, it is becoming both more powerful and more widely applicable. The top three benefits of IIoT sensors are:

  • Their ability to monitor assets and collect data around the clock,
  • Their relative cost,
  • Their ability to communicate with other computer systems.

Increased monitoring and data collection

The addition of IIoT sensors to existing assets or processes allows for real-time data tracking. By providing 24/7 monitoring, sensors can send alerts to the maintenance team as soon as potential problems arise, which means faster repair and more uptime.

The information being collected by a sensor attached to an equipment can also be instantaneously sent to a remote location where the data can be compiled.

For example, when applying predictive maintenance strategies, IIoT vibration sensors attached to rotating machinery can give you an accurate view of the asset’s operational condition by knowing its rotational speed and vibration characteristics at any given time.

Cost savings

Sensors have dropped in price in recent years, making them an affordable investment. Sensors are the least expensive they ever have been, leading to quicker returns on investment. Ultimately, sensors will save a facility money because the plant is able to produce more with less effort and less cost. Thus, the inverse of cost savings also comes to fruition - revenue increases.

A practical example to illustrate revenue generation with the use of IoT sensors is by understanding how machines work and how they wear out. By having IoT sensors that constantly check multiple parts of an equipment, maintenance teams can more accurately pinpoint the components that may be at risk. This generates significant savings from simply replacing or servicing components instead of having to replace the whole asset.

Moreover, an understanding of equipment health allows for a more efficient product life cycle management. Assets can be more accurately and effectively serviced as needed, therefore prolonging its useful life and increasing its productivity.

Integration capabilities

Sensors can easily integrated into many types of software, most notably a CMMS software. The sensors are near continuously collecting data, but all of that data must be analyzed. Integrating these sensors into a CMMS or other software allows algorithms to process IIoT data. This provides valuable insights to teams and supports better management decision making.

Multiple sensors measuring various aspects of an equipment’s operation allows a robust historical collection of data. Various historical data sources can describe the conditions that an asset was experiencing right before an occurrence of failure or near miss. These data sources can then build a model that predicts failure events, therefore allowing the teams to perform proactive solutions.


IIoT sensors are an important addition to the maintenance professional’s arsenal of tools. The physical sensors connect and send information to the cloud, where it is processed. Once processed, data is sent to end-users in a digestible way. Users then may take any necessary actions (if action is not automated) based on the data.

They provide inexpensive means of giving you 24/7 access to all your critical equipment. As time goes on, this hardware is becoming less expensive - making it a more and more worthwhile investment. A complete sensor system results in fewer maintenance emergencies and greater productivity overall.

Want to keep reading?

Industrial IoT Sensors: What Are They and Which Businesses Use Them

Industrial IoT sensors are widely used in different industries to monitor equipment, assets, systems, and overall performance.
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What are the most common types of IIoT sensors available?

Dozens of sensors are already available to monitor, track, and report on critical aspects of your operations with more under development each day.
View Article

What industries can use IIoT sensors?

Any industry that uses or maintains equipment can make use of IIoT sensors. A few of them include agriculture, manufacturing, and retail.
View Article


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