Passive Moisture Sensors Explained

Passive Moisture Sensors Explained

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Passive Moisture Sensors are opening a new frontier of environmental sensing where traditional sensing technology cannot go.  See how passive RFID sensors detect and log moisture data.

Passive Moisture Sensors

Continuing with our series of articles around Passive Sensors, in this article we take a look at one of the most popular types of passive sensor, passive moisture sensors.

Detecting Moisture with Passive RFID sensors

Metalcraft knows the significance of moisture in processes and materials; we’ve produced a range of waterproof tags and labels for many years. Today, we have new technology – passive moisture sensor tags – to help you measure the presence of water in all sorts of powerful ways.

Monitoring Changing Moisture and Humidity

Moisture sensing has been around for some time in cars, offices, museums, warehouses, greenhouse and factories. It’s not uncommon to monitor environmental and material moisture content in grain and other foods as well as building materials.

However, wired sensors are connected to power, requiring high installation costs, and traditional wireless sensors have relied on batteries, creating bulky form factors and requiring replacement costs.

Advantages of Passive RFID Sensor Moisture Tags

Metalcraft’s new passive moisture sensing tags hold tremendous advantage over existing moisture sensors working where active or semi-active sensors are not practical.

At Metalcraft, we are opening a new frontier deploying and sensing where existing technology cannot go.  Metalcraft’s moisture sensing tags are much smaller, thinner and more flexible than battery-powered sensors, and they are more cost efficient than active wireless sensing tags. In fact, their low cost makes them a viable option for disposable or high volume type applications.

RFID passive sensors also have advantages over other types of wireless sensing technologies. Using RFID passive sensors, readers can read many RFID tags with one reader lowering infrastructure and hardware maintenance costs. RFID sensors also can transmit data with error correction codes helping ensure accurate data.  Sensor tethering and ability to operate in a wider temperature extremes sets these sensors apart from other wireless sensors.  Also with the ability of new on-metal RFID sensor tags, applications of almost any type can be undertaken.  

Ultimately putting more tags in more places will provide high quality data in construction materials, manufacturing controls, agriculture and food production and much more.

Download: Passive RFID Moisture Sensors Explained

How Do Wireless Passive Sensors Detect Moisture?

Passive sensors identify the presence of moisture by detecting changes in antenna impedance of the object being sensed.  Based upon the impedance level found by the tag’s integrated circuit, that tag transmits back a sensor code that can be correlated to determine the level of moisture. Software then can display, log and perform various calculations to provide useful analysis about the object being sensed.   

Since the moisture sensor tags return simple 5 -bit code based upon what it senses, and not an actual unit of measurement, these values can be used to correlate the presence or level of moisture on almost any object including wood, plastic and metal.  The passive sensor’s antenna design and adjustable environmental tuning provide a highly customizable sensing solution for almost any application.

Metalcraft makes durable, flexible passive moisture sensor tags that work using standard UHF frequencies (915/868 MHz).  These tags can be affixed or embedded into most materials and have an average read range of 15-22 feet.  Impedance changes are wirelessly communicated to standard EPC Gen 2 readers and interpreted with a software applications.

RFID moisture sensor applications

Beyond the current range of uses for RFID moisture sensors, the small form factor and low cost afford a wide range of new uses for automotive, construction, healthcare and many other industries.

For automakers, we know passive moisture sensors can support automotive quality control, autonomously detecting leaks in assembled vehicles with pinpoint accuracy. With the complexity of automotive, aircraft and vehicle assemblies, solving water intrusion at the factory greatly reduces costs and improves customer satisfaction.

For health care workers, these low-cost moisture sensor tags can wirelessly detect incontinence events, reporting the status without disturbing the patient. The benefits here include patient health and dignity and caretaker satisfaction in the context of millions of brief changes each day.

For building and construction managers, passive sensor tags can now sense the moisture of wood and other building materials. The battery-free tags can monitor humidity inside sheets of plywood or building up inside building walls where mold can grow out of sight. Quality construction and maintenance improve profitability, health and safety.

For road and bridge maintenance, inexpensive moisture ingress monitoring in road beds and bridge decks can provide engineers with data for scheduling preventative maintenance and help transportation officials determine which surfaces are experiencing greater issues and needing repair or replacement.

Metalcraft Delivers Passive Moisture Sensing

Passive moisture sensing tags can serve the existing sensor markets at much lower cost and create opportunity for new market applications – new ways to access quality-related data using large numbers of wireless, maintenance-free sensors.

Investing in passive sensor tags creates powerful new efficiency and competitive advantage; making it easier to provide data that keeps materials dry, equipment safe and much more. This new class of technology significantly lowers the cost of ownership, speeding the dawn of the Internet of Things.

As you consider the value of wireless sensing for your business, know that Metalcraft is ready with affordable, durable RFID moisture tags. We encourage you to contact a Metalcraft ID Specialist at 800-437-5283 to explore this new technology today.


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