9 Interesting Wireless IoT Sensor Types and Their Applications
Wireless sensors are the backbone of IoT and its industrial counterpart the Industrial Internet of Things (IIoT). In a previous blog post, we talked about some of the more popular sensor types such as temperature, pressure, and accelerometers. In this blog, we discuss a few more interesting wireless IoT sensor types on the market.
Wet Bulb Temperature
Whereas standard, or dry bulb temperature sensors do not take moisture in the air into account when reporting the temperature, wet-bulb temperature sensors provide measurements closer to the true (thermodynamic) temperature. A wet-bulb sensor is essentially a thermometer covered in a water-soaked fabric over which air is passed. In drier, less humid air, the water on the cloth evaporates more quickly, whereas in more humid conditions, the moisture in the air causes the water in the cloth to evaporate more slowly.
When used in conjunction with a dry bulb sensor, a wet bulb temperature sensor can calculate measurements such as relative humidity (difference between the two sensors) and dew point (the temperature at which water starts to condense and form droplets). These measurements are useful in number of applications for humidity control to help avoid condensation within a building which can lead to discoloration, mode/mildew growth and structural damage.
Enhanced Voice Recognition using Facial Vibrations
Voice recognition and applications that use it are everywhere, from virtual assistants to our phones, tablets, and automobiles. However, the voice recognition capabilities in these systems are not always reliable, as they might not understand our voices clearly enough in the presence of ambient or environmental noise.
A new hardware approach is being used to improve voice recognition. This technology uses a laser-based sensor to measure tiny vibrations in a person’s throat and face when they speak. The laser greatly augments the system’s accompanying microphone signal by filtering out background noises and providing an isolated near-perfect signal.
There are many use cases for this technology including, voice recognition in automotive, virtual reality, aviation, industrial handsets and wearables.
Structural Health Monitoring Sensors
Structural Health Monitoring (SHM) refers to the use of sensors for collecting and analyzing data, over the service life of structures such as bridges. Instead of reacting to damage that is already occurring, SHM is more about proactive maintenance through the continuous assessment of the structural integrity in bridges and other structures. For example, bridge design must consider factors such as vibration, wind, weather, and traffic alongside the damage that they can cause. Without SHM sensors, inspectors must rely on visual inspection.
There are many types of wireless IoT sensors used in Structure Health Monitoring. Accelerometers can help identify vibration-based damage, while anemometers on suspension bridges monitor wind speed and direction that potentially impact their integrity.
Ultraviolet Radiation Detection
Exposure to radiation can be deadly. When the exposure is high enough, it can remove an electron from an atom. If it reaches human skin cells, the risk of DNA damage and skin cancer is significant. People working with or around radioactive substances wear a device known as a dosimeter. Dosimeters contain phosphor crystals that are designed to trap electrons freed by harmful ionizing radiation.
When heated, the crystals release trapped electrons in the form of light. These electrons can be measured to determine the amount of radiation its wearer has been exposed to. On the consumer side, ultra-violet (UV) detection wearables, apps and stickers have recently been developed to monitor and prevent dangerous levels of sun exposure, and many of these devices use dosimeters.
Air Pollution Sensors
Air pollution is a major problem in cities around the world. While air pollution detection is usually handled by governmental agencies, advances in technology are allowing individuals and community groups to monitor and detect air pollution around their homes, schools, and parks. Two types of air pollution sensors are particulate matter sensors and gas phase sensors.
Particulate matter sensors can detect particulates using either optical particle counting or volume scattering. In the former, particles entering the sensor are individually sized and counted based on how they scatter light. In the latter, particles enter the sensor scatter light from an internal light source.
Gas phase sensors detect gasses such as nitrogen oxide and ozone using a number of different techniques. Ozone and nitrogen dioxide detectors use electrochemical cells to detect gasses as they pass through air or using a metal oxide semiconductor.
Snow Level Monitoring
Another interesting wireless IoT sensor use case is the monitoring of snow levels in real time. Snow-related sensors can help skiers determine the quality of ski tracks and can even help with avalanche prevention.
Snow depth can be measured using a variety of methods including ultrasonic and/or laser sensing. In the case of ultrasonic sensors, the sensor is placed at a point where the snow level is to be measured. This sensor continuously captures data on the snow depth and sends it to the microcontroller.
Identification of Storage Incompatibilities
In today’s global economy, goods are continually transported between continents using sea containers. Accidents with and mismanagement of these containers can cause significant problems to the parties involved in the transaction as well as the environment. One method of preventing problems is to use wireless IoT sensors to monitor the logistics of such operations.
Sensors within one container exchange information with other pallets or containers stored around it, using RFID and similar technologies. For example, if a pallet of dangerous goods is located next to a pallet with flammable materials, warning messages can be sent. This allows corrective measures to be taken before a problem occurs.
Poor water and sanitation conditions contribute to illness and millions of deaths worldwide. Conventional water monitoring processes are manual, time-consuming and do not provide real-time results. Wireless IoT sensor nodes offer a promising alternative as they can detect parameters related to water quality such as pH, electrical conductivity, oxidation reduction and turbidity. Like other use cases, real-time water quality monitoring enables early warning abilities and timely response in the event of water contamination.
Radiation from the sun is received as wavelengths known as the solar spectrum. A pyranometer is a type of sensor that converts received solar radiation into an electrical signal that can be measured.
There are several use cases / applications that use solar radiation measurements including:
- Measuring the efficiency of solar panels in converting the sun’s energy into electricity.
- Determining when solar panels need to be cleaned.
- Golf and park maintenance including the scheduling of irrigation.
- Weather prediction models in meteorology.
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