New weather feed online

The new Xively feed is here:

Data being logged is:

  • indoor temperature
  • indoor humidity
  • outdoor temperature
  • outdoor humidity
  • air pressure
  • total rainfall (since the weather station was set up)
  • light levels (on my study desk, but will be outdoor soon)
  • wind speed, gust speed and direction

The iPhone app simply creates a list of the elements in the datastream, so it is consistent. I also figured out how to display the units in the app.

Putting it all back together

After merging the XC0348 code I had which was receiving the data transmitted by the outdoor sensors with the Xively code there was a bit of tweaking to do to get the sketch to play nicely. The last step was to add the code back for the pressure sensor. This was problematic as the sensor uses I2C and soon as I added the Wire library the whole thing stopped running properly. After some reading I wondered if I was just running out of memory so I commented out a whole lot of serial print statements and it this got things working again. Of course, without the print statements there was a whole lot less debugging going on.

A couple of things that still need attention:

  • the pressure sensor has been timing out often, so I get false values where a negative error code is returned. I’ve increased the timing loop and am seeing if this works better
  • we had a heap of rain overnight and my rainfall figure suddenly dropped because I was only using the LSB, and the count had overflowed. A bit of trial and error and now it is showing the true total. A problem with rainfall is that the sensor reports total rainfall, so this will just keep going up and up. I need some way to keep daily totals. Perhaps I need to add a real time clock?
  • my light values are related to the resistance in the photoresistors, so the curves are inverted i.e. when it is light the value is lowest FIXED Apr 10 – I chose an arbitrary dark value of 1000 and am using that as a reference point to subtract from, so now a bigger value does mean more light rather than more dark!
  • wind direction is returned as an integer between 0 and 31, which seem to correspond to 16 compass points. I think there might be some sort of moving average calculation used by the base station to reduce errors due to rapidly fluctuating wind shifts.