I2C Humidity Sensor
From Openmoko
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The relative humidity depends on the ambient temperature. This makes it rather difficult to find the best mounting place for the sensor. The requirements are: | The relative humidity depends on the ambient temperature. This makes it rather difficult to find the best mounting place for the sensor. The requirements are: | ||
* contact with fresh air | * contact with fresh air | ||
| − | * minimize errors introduced through | + | * minimize errors introduced through heat from other electronic components. |
==Possible mounting places== | ==Possible mounting places== | ||
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I tried the first two options. After drilling small holes both places can be used, but even without top cover I was able to measure a temperature difference of about one degree celsius between the inside and outside of the case. | I tried the first two options. After drilling small holes both places can be used, but even without top cover I was able to measure a temperature difference of about one degree celsius between the inside and outside of the case. | ||
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Latest revision as of 17:49, 9 September 2010
[edit] General description
The SHT21 from Sensirion is a digital humidity and temperature sensor with a easy to use I2C interface. It connects to your Freerunner just like the I2C Pressure Sensor.
A simple kernel driver is already available from here.
[edit] Mounting
The relative humidity depends on the ambient temperature. This makes it rather difficult to find the best mounting place for the sensor. The requirements are:
- contact with fresh air
- minimize errors introduced through heat from other electronic components.
[edit] Possible mounting places
- next to the GPS antenna
- inside the GSM antenna
- behind the speaker holes
- ...
I tried the first two options. After drilling small holes both places can be used, but even without top cover I was able to measure a temperature difference of about one degree celsius between the inside and outside of the case.
