This document compares two types of humidity sensors: the HIH series from Honeywell and the SHT series from Sensirion. The HIH series operates from 4-5.8V, has a response time of 15 seconds, and costs $35-40 per unit. The SHT series has a faster response time of under 4 seconds, lower power consumption of 30uW, operates from 2.8-5.5V, costs $18-24 per unit, and measures both humidity and temperature with a single digital sensor. After considering factors like cost, response time, power consumption, and output format, the document concludes the SHT series is better suited for the author's application.

1. Humidity Sensor
Presented by:
Key Kai Wong

2. Outline
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What is Relative Humidity
Manufacturers of Humidity Sensor
Humidity Sensor from Honeywell ( HIH series)
Humidity Sensor from Sensirion ( SHT Series)
Comparision..
Conclusion
Reference

3. What is Relative Humidity (RH)
Measurement - Relative humidity (RH) is the amount
of water vapor in the air compared with the amount of
vapor needed to make the air saturated at the air's
current temperature
Example:
At 3 p.m. the air has 9 grams of water vapor per cubic
meter of air. We divide 9 by 30 and multiply by 100 to get
a relative humidity of 30%

4. Water vapor air can hold in degrees C
30 degrees
20 degrees
10 degrees
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30 grams per cubic meter of air
17 grams per cubic meter of air
9 grams per cubic meter of air

5. Manufacturers of Humidity Sensor
Honeywell
( HIH series )
Sensirion
( SHT Series )

6. Humidity Sensor from Honeywell
( HIH series)
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Packages are chemically resistant
operate in ranges of -40 °C to 85 °C (
-40 °F to 185 °F)
Response time -15 sec in slowly moving
air at 25 °C
Low power design – 200 microA @ 5
Vdc
Operating volatge 4 – 5.8 v
On-chip signal processing ensures
linear voltage output versus %RH.
$35 - $40 per unit price

8. HIH-3610 Series

9. Humidity Sensor from Sensirion
( SHT Series )
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2 sensors for relative humidity & temperature
Very easy-to-use due to calibration & digital 2wire interface
Calibrated & digital output (2-wire interface)
Fast response time < 4 sec.
Temp. accuracy: +/- 0.5°C @ 25 °C
Low power consumption (typ. 30 µW)
Operating Voltage 2.8 - 5.5v
Cost $18 - $24 per unit price

11. Series interface

13. Comparision..
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Honeywell
( HIH series )
Response time -15 sec in slowly
moving air at 25 °C
Low power design – 200 microA @ 5
Vdc
Operating volatge 4 – 5.8 v
$35 - $40 per unit price
On-chip signal processing ensures
linear voltage output versus %RH.
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Sensirion
( SHT Series )
Fast response time < 4 sec.
Low power consumption (typ. 30
µW)
Operating Voltage 2.8 - 5.5v
Cost $18 - $24 per unit price
2 sensors for relative humidity &
temperature
Very easy-to-use due to calibration &
digital 2-wire interface
Calibrated & digital output (2-wire
interface)
Temp. accuracy: +/- 0.5°C @ 25 °C

14. Conclusion
After considering the aspect of the operating
voltage, cost, response time and the output of
the sensor. Sensor SHT series is more suitable
for our application.

15. References
• Honeywell
http://content.honeywell.com/sensing/prodinfo/humiditymoisture/#applications
• Sensirion
http://www.sensirion.com/en/sensors/humidity/default.htm
• USToday
http://www.usatoday.com/weather/wrelhum.htm