Hygrometer

From SensorWiki

Sensors Interfaces Communications Tutorials References
Table of contents

Summary

Introduction

A hygrometer is an instrument used to sense humidity. Simple hygrometers are usually of the "wet bulb" or hair varieties. A "wet bulb" hygrometer contains two thermometers, with the bulb of one thermometer kept wet so that evaporation lowers its temperature - for temperatures above freezing, comparing the output of the two thermometers yeilds information on the ambient humidity. A "hair" hygrometer measures the relative length of a stretched human or animal hair, which changes relative to the ambient humidity.

Capacitive humidity sensors are also available, such as the BCcomponents 2322 691 90001, in which a non-conductive foil is covered on both sides with a layer of gold. The dielectric constant of the foil changes as a function of ambient humidity, altering the capacitance value of the sensor. (BCcomponents)

Humidity sensors have been used to detect finger contact at shakuhachi holes (Kanamori et al. 1993).

Devices

Source Country Price
Digikey (http://www.digikey.ca/) Canada CAN$ 15.08

BCcomponents 2322 691 90001

10-90%RH Capacitive Atmospheric Humidity Sensor

Variants:
Datasheet: [1] (http://rocky.digikey.com/WebLib/BC%20Components/Web%20Data/2322%20691%2090001.pdf) (.pdf)
Resources:
Notes:


Source Country Price
Infusion Systems (http://infusionsystems.com/) Canada US$ 108.25

Infusion Systems Hot&Humid v1.1

10-95%RH Capacitive Atmospheric Humidity and Temperature Sensor

Variants:
Datasheet: [2] (http://infusionsystems.com/catalog/product_info.php/products_id/67)
Resources:
Notes:


Media

Images
Video
Circuits

References


Sensors Interfaces Communications Tutorials References