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Low cost
3 to 5V power and I/O
2.5mA max current use during conversion (while requesting data)
Good for 20-80% humidity readings with 5% accuracy
Good for 0-50°C temperature readings ±2°C accuracy
No more than 1 Hz sampling rate (once every second)
Body size 15.5mm x 12mm x 5.5mm
4 pins with 0.1" spacing
Applications: Arduino + Humidity Sensor + Temperature Sensor
Sensor details: https://www.youtube.com/watch?v=C7uS1OJccKI
Setting up sensors video: https://www.youtube.com/watch?v=Qj69qfneNzI
Setting up sensors video2: https://www.youtube.com/watch?v=Rppuxjc_Rzc
Raw basics: http://www.instructables.com/id/Arduino-Temperature-Humidity/
Arduino code: http://playground.arduino.cc/Main/DHTLib
DHT11 power consumption
Figure 2. Power consumption sheet.
Humidity Sensor DHT11 component can be used with batteries. For example AA battery 400-900 mAh.
Battery Life = Battery Capacity in Milli amps per hour / Load Current in Milli amps * 0.7
Battery Life = 750~ mAh / 0.2 mA * 0.7 = 2600~ Estimated Hours.
Arduino requires about 46.5 mA current in order to operate properly and sleeping power consumption 34.4 mA.
DHT11 material (used in component)
‘This sensor includes a resistive-type humidity measurement component and an NTC temperature measurement component, and connects to a highperformance 8-bit microcontroller, offering excellent quality, fast response, anti-interference ability and cost-effectiveness.’ [8]
So basicly humidity sensor is made out of regular material such as silicon microchip, ceramic body and plastic casing?
Relative Humidity
‘Relative humidity is the ratio of the current absolute humidity to the highest possible absolute humidity (which depends on the current air temperature). A reading of 100 percent relative humidity means that the air is totally saturated with water vapor and cannot hold any more, creating the possibility of rain. This doesn't mean that the relative humidity must be 100 percent in order for it to rain -- it must be 100 percent where the clouds are forming, but the relative humidity near the ground could be much less.’ [2]
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The higher the percentage, the more humid. The higher the relative humidity, the less drying takes place. This affects the human bodies' perception of heat, as explained next.’ [3]
Figure 32. [7]
Figure 43. [7]
Capacitive Humidity Sensor and Physical principles models
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To actually get any usable humidity values, a relatively accurate temperature measurement is also needed, as relative humidity is very dependant on temperature.
Figure 4. Capacitive Humudity Sensor Schematic.
http://www.arduino.cc/en/Tutorial/CapacitanceMeter
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Figure 5. Timing Diagram. [5]
Applications: Arduino + Humidity Sensor + Temperature Sensor
Sensor details: https://www.youtube.com/watch?v=C7uS1OJccKI
Setting up sensors video: https://www.youtube.com/watch?v=Qj69qfneNzI
Setting up sensors video2: https://www.youtube.com/watch?v=Rppuxjc_Rzc
Raw basics: http://www.instructables.com/id/Arduino-Temperature-Humidity/
Arduino code: http://playground.arduino.cc/Main/DHTLib
DHT11 power consumption
Figure 6. Power consumption sheet.
Humidity Sensor DHT11 component can be used with batteries. For example AA battery 400-900 mAh.
Battery Life = Battery Capacity in Milli amps per hour / Load Current in Milli amps * 0.7
Battery Life = 750~ mAh / 0.2 mA * 0.7 = 2600~ Estimated Hours.
Arduino requires about 46.5 mA current in order to operate properly and sleeping power consumption 34.4 mA.
DHT11 material (used in component)
‘This sensor includes a resistive-type humidity measurement component and an NTC temperature measurement component, and connects to a highperformance 8-bit microcontroller, offering excellent quality, fast response, anti-interference ability and cost-effectiveness.’ [8]
So basicly humidity sensor is made out of regular material such as silicon microchip, ceramic body and plastic casing?
Summary
‘Humidity sensors are sensors that convert the moisture content in air, gases, bulk materials or soil into an electric output signal.
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