資料擷取與感測器 應用實務

溫濕度感測器 Temperature & Humidity Sensor Temperature Sensor ( Thermometer) A thermometer is a device that measures temperature or temperature gradient using a variety of different principles. A thermometer has two important elements: the temperature sensor (e.g. the bulb on a mercury-in-glass thermometer) in which some physical change occurs with temperature, plus some means of converting this physical change into a numerical value (e.g. the visible scale that is marked on a mercury-in-glass thermometer). http://en.wikipedia.org/wiki/Temperature_sensor

溫濕度感測器 Temperature & Humidity Sensor Temperature Sensor ( Thermometer) http://en.wikipedia.org/wiki/Temperature_sensor

溫濕度感測器 Resistance thermometer Resistance thermometers, also called resistance temperature detectors (RTDs), are sensors used to measure temperature by correlating the resistance of the RTD element with temperature. Most RTD elements consist of a length of fine coiled wire wrapped around a ceramic or glass core. The element is usually quite fragile, so it is often placed inside a sheathed probe to protect it. The RTD element is made from a pure material, platinum, nickel or copper. The material has a predictable change in resistance as the temperature changes; it is this predictable change that is used to determine temperature. http://en.wikipedia.org/wiki/Resistance_thermometer

溫濕度感測器 Thermocouple http://en.wikipedia.org/wiki/Thermocouple A thermocouple consists of two dissimilar conductors in contact, which produce a voltage when heated. The size of the voltage is dependent on the difference of temperature of the junction to other parts of the circuit. Thermocouples are a widely used type of temperature sensor for measurement and control and can also be used to convert a temperature gradient into electricity. Commercial thermocouples are inexpensive,interchangeable, are supplied with standard connectors, and can measure a wide range of temperatures. In contrast to most other methods of temperature measurement, thermocouples are self powered and require no external form of excitation. The main limitation with thermocouples is accuracy; system errors of less than one degree Celsius (°C) can be difficult to achieve. http://en.wikipedia.org/wiki/Thermocouple

溫濕度感測器 Temperature & Humidity Sensor Humidity Sensor ( Hydrometer) A hygrometer is an instrument used for measuring the moisture content in the environment. Humidity measurement instruments usually rely on measurements of some other quantity such as temperature, pressure, mass or a mechanical or electrical change in a substance as moisture is absorbed. By calibration and calculation, these measured quantities can lead to a measurement of humidity. Modern electronic devices use temperature of condensation, or changes in electrical capacitance or resistance to measure humidity changes. http://en.wikipedia.org/wiki/Hygrometer

溫濕度感測器 Temperature & Humidity Sensor Humidity Sensor ( Hydrometer) Relative humidity is the ratio of the partial pressure of water vapor in the air-water mixture to the saturated vapor pressure of water at those conditions. The relative humidity of air is a function of both its water content and temperature. Relative humidity is an important metric used in weather forecasts and reports. In hot summer weather, a rise in relative humidity increases the apparent temperature to humans (and other animals) by hindering the evaporation of perspiration from the skin. For example, according to the Heat Index, a relative humidity of 75% at 80°F (27°C) would feel like 83.574°F ±1.3 °F (28.652°C ±0.7 °C) at ~44% relative humidity. http://en.wikipedia.org/wiki/Humidity

溫濕度感測器 Temperature & Humidity Sensor Humidity Sensor ( Hydrometer) The dew point is the temperature below which the water vapor in a volume of humid air at a given constant barometric pressure will condense into liquid water at the same rate at which it evaporates. Condensed water is called dew when it forms on a solid surface. The dew point is associated with relative humidity. A high relative humidity indicates that the dew point is closer to the current air temperature. Relative humidity of 100% indicates the dew point is equal to the current temperature and that the air is maximally saturated with water. When the dew point remains constant and temperature increases, relative humidity decreases. http://en.wikipedia.org/wiki/Dew_point

溫濕度感測器 Temperature & Humidity Sensor http://www.seeedstudio.com/depot/grove-temperaturehumidity-sensor-pro-p-838.html?cPath=144_147 http://www.seeedstudio.com/wiki/Grove_-_Temperature_and_Humidity_Sensor_Pro 感測器生產廠商http://www.silabs.com/products/sensors/humidity-sensors/Pages/default.aspx