Sunday, December 12, 2010

Weather station update!

It has been quite a while since I last posted here, it was a busy year! I became a father, and that took a lot of the time available to report - I still get quite some time to do the things, only no time to spend here reporting :) , but I hope to revive it now!

So here is an update on the weather station!

Finally, after 11 and a half months the thing died! in the coldest night of the year, after sending a packet indicating -8.1C outside at 3 in the morning...

funnily enough, the FS20 switch that turns the boiler on and off died (stopped receiving) at approximately the same time...can't explain it, it wasn't cold in the room where that one is located...

It sent 51273 messages on a set of 3AA GP branded units, which were not new when it was put outside. Since for each packet I measured the wind for 1 second, this means the JeeNode was in full power mode for a bit over 14 hours.

Anyway, I opened it, days later, and when the temperature outside was up to -1 and the batteries read about 1.9V, or about 0.6V per cell.

I wonder if the fact that the Atmega runs at 16MHz, which is out of the specs at 3.3V (let alone 1.9V), contributed to it failing at low temperature/very low voltage as well, or if it could have been pushed any harder! It is out now with a new set of batteries, since 8/12/2010, but I need to redo the anemometer, so I don't think these batteries will be out until they die!

I think this was a victory for a JeeNode in low power mode!

As for the FS20 switch, I still do not know what happened...It just would not receive, until I moved it to a different place, where reception is fine. I wonder if all the snow on the roof created some effect, which prevented it from working properly. Maybe i should try now that the snow melted. However, if that is the case, then I definitely can not leave it there, as it is precisely when it is cold and snowy outside that I need it the most!
Plans are on the making anyway for a JeeNode OpenThem controler, which should be comming soon. I already developed the control loop (PI) which determines the desired water temperature, now I just need to adjust the PI coeficients and implement the hardware, for which most components are already in the house!

I hope to report before the new year again on another project!

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