Alexander Leidinger

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Sep
01

Weather sta­tion read­out with FreeBSD

A while ago a wind tur­bine was installed not far away from my place. It is far enough to not dis­turb us, and it is near enough to notice that it turns a lot (IIRC I have seen it only once not turning).

This trig­gered a ques­tion. How much energy would such a device (smaller of course) pro­duce at my place?

The answer depends upon sev­eral fac­tors. The wind speed, the wind direc­tion and the wind-speed-to-power-output curve of the device. If you do not take a device which rotates around the hor­i­zon­tal axis but the ver­ti­cal axis, the wind direc­tion can be taken out of the ques­tion (prob­a­bly not com­pletely, but to answer my ques­tion this sim­pli­fi­ca­tion should be ok). The output-power curve depends upon the device, and I hope it is easy to get it from the ven­dors. The remain­ing open ques­tion it the wind speed at my place. Is there enough wind with enough speed?

To answer this ques­tion I bought a weather sta­tion with an anemome­ter (wind speed sen­sor). I searched a lit­tle bit until I decided to buy a spe­cific one (actu­ally I bought three of them, some cowork­ers got inter­ested too but they found only much more expen­sive ones, so soon there will be three more weather sta­tions in use in Bel­gium, France and Ger­many). The main point is, I can con­nect it to an USB port of a PC and there is some soft­ware for Linux to read out the data. It also comes with some other outdoor-sensors (tem­per­a­ture, rain, wind direc­tion, humid­ity, …) and an indoor-control-unit with some inter­nal sen­sors (tem­per­a­ture, humid­ity). The user inter­face is mainly the touch­screen of the control-unit. There is also some Win­dows soft­ware, which is needed to pro­gram the inter­val in which the mea­sure­ments are taken and saved in the control-unit.

It seems the weather sta­tion is pro­duced by Fine Off­set Elec­tron­ics Co.,Ltd and sold within dif­fer­ent brands in dif­fer­ent loca­tions. The Linux soft­ware can read all of them, as the ven­dor and prod­uct IDs are not changed.

Port­ing the soft­ware was easy, it uses libusb and I just had to cor­rect a lit­tle prob­lem for the non-portable func­tions which are used (I asked about them on usb@ and the response was that they just got imple­mented upon my request and will be com­mit­ted to HEAD soon). I made a lit­tle patch for the soft­ware to only use them when avail­able (if you have not loaded the USB HID dri­ver, you do not need to care about them) and com­mit­ted it to the Ports Col­lec­tion as astro/fowsr.

Now I just need to attach the out­side sen­sors at the place where I would put the ver­ti­cal axis wind tur­bine, install some toolkit which takes a series of mea­sure­ments and dis­plays them as a nice graph (while keep­ing all data val­ues) and write some glue code to feed the out­put of fowsr to it. After a year I can then cal­cu­late how much power a given wind tur­bine would have pro­duced dur­ing the year and cal­cu­late the return of invest­ment for it.

The Linux soft­ware also ref­er­ences sev­eral weather sites, for some of them you can get even an iGoogle wid­get so that you can view the data from wher­ever you want (as long as you have a suit­able inter­net con­nec­tion). I think this is also some­thing I will have a look at later.

Note to users in Europe, the device also comes with a DCF77 receiver. As the time is dis­trib­uted in UTC+1 (or +2, depend­ing on the day­light sav­ing time), you should adjust the time­zone set­ting accord­ingly to this, not to plain UTC (so for me the time­zone should be ‘0’ for the same timezone).

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Weather sta­tion read­out with FreeBSD, 9.5 out of 10 based on 2 ratings
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6 Responses to “Weather sta­tion read­out with FreeBSD”

  1. Tweets that mention Weather station readout with FreeBSD | Alexander Leidinger -- Topsy.com Says:

    […] This post was men­tioned on Twit­ter by FreeBSD Project, Manuel Tru­jillo. Manuel Tru­jillo said: RT @freebsd: BLOG: Weather sta­tion read­out with FreeBSD: A while ago a wind tur­bine was installed not far away from… http://bit.ly/9y6uT6 […]

  2. Johannes Says:

    Sounds inter­est­ing, do you mind to tell your read­ers which device exactly you ordered and where? I am also look­ing for such a device, and FreeBSD com­pat­i­bil­ity would be a plus, of course :)

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  3. netchild Says:

    Go to http://www.perl.de (when they fixed the PHP error which cur­rently shows up) and search for a weather sta­tion at around 100 EUR (99,xx EUR). If it has a USB port and they tell about some Easy­Weather soft­ware, it is the right one. If you go to the ven­dor home­page and have a look at the pro­fes­sional sta­tions, it is one of the 2 touch­screen ones (I do not know the dif­fer­ence between them).

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  4. netchild Says:

    Oops, http://www.pearl.de

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  5. Manu Says:

    it’s the pearl FreeTec px1117
    which is the Fine Off­set WH1080 or WH1081
    hard to see which one from web­site descrip­tion.
    http://www.foshk.com/Weather_Professional/index.htm
    i cur­rently use it with the win­dows soft­ware called “cumu­lus”, i find it bet­ter than easy­weather as it dis­plays more wind sta­tis­tics.
    Speak­ing of green energy, that sta­tion lack of a solar meter.
    Noway to do the same study for a solar panel Alexan­der ;)
    But it’s accu­rate and cheap (same model of an other brand can cost 50 euro more !!!) i would even rec­om­mend it for a young sci­en­tist (as a gift), if i was still a teen, i’m sure i had bother my par­ents to buy it.

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  6. Johannes Says:

    Thanks!

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