View source for I2C Humidity Sensor

From Openmoko

Jump to: navigation, search

You do not have permission to edit this page, for the following reasons:

  • The action you have requested is limited to users in the group: Administrators.
  • You must confirm your email address before editing pages. Please set and validate your email address through your user preferences.

You can view and copy the source of this page:

Return to I2C Humidity Sensor.

Personal tools

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.


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 external heat from other electronic components.

Possible mounting places

  • next to the GPS antenna
  • inside the GMS 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.