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).

6 thoughts on “Weath­er sta­tion readout with FreeBSD”

  1. Pingback: Tweets that mention Weather station readout with FreeBSD | Alexander Leidinger -- Topsy.com
  2. 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 🙂

    1. 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).

  3. it’s the pearl FreeTec px1117
    which is the Fine Off­set WH1080 or WH1081
    hard to see which one from web­site de­scrip­tion.
    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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