Humidity Sensors

Before understanding humidity sensors, one must first understand what humidity is. “Humidity refers to the water vapor content in air or other gases.” A humidity sensor measures and regularly reports the relative humidity in the air. As Kayleigh's post says, "hygrometer is the proper name for an object which measures humidity or moisture content.” The most commonly used type of humidity sensor relies on the ability of two nearby electrical conductors to create an electrical field between them. A source describes the process; “A polymer film on the conductors collects moisture from the air, and the moisture causes minute changes in the voltage between the two plates. The changes in voltage are converted into digital readings showing the amount of moisture in the air.” Humidity sensors then use the information collected to help regulate the space.

Humidity sensors are helpful in everyday residential uses. For example, people who suffer from conditions that are affected by high humidity, such as allergies or asthma, can have humidity sensors installed in their homes to control humidity. Humidity sensors are also very useful for medical purposes. Hospitals generally use humidity sensors to carefully maintain humidity in spaces containing sick patients. These sensors can also be very useful in spaces that store objects damaged by exposure to moisture. Examples include wine cellars, humidors, greenhouses, or antique storage areas. 

Humidity sensors are also an important part of building design, especially as we move towards green and energy efficient buildings. In an article entitled “Putting Building Science Into Practice,” a retrofit project of Fraunhofer’s new Boston headquarters is discussed. The rehab project aims to test emerging build technologies. One of these technologies relies on the use of humidity sensors to measure its efficiency. “The Showcase building will try many types of insulation on the walls, including vacuum panels that use gas, rather than cellulose or fiberglass, as the actual insulator.” The humidity sensors will collect data that will be used to determine the comparative advantages and worth of the new technology.

When reading over other student’s posts, I found Matthew's post about flow sensors to be very interesting. The comparison he made between the displacement method and the bucket and the stopwatch helped to simplify the method and make it easy to understand.

http://www.technologyreview.com/view/510131/putting-building-science-into-practice/

http://EzineArticles.com/4695977

http://www.wisegeek.com/what-is-a-humidity-sensor.htm

http://www.sensorsmag.com/sensors/humidity-moisture/choosing-a-humidity-sensor-a-review-three-technologies-840