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7 months of sending and still going

My Funky+DS18B20 temperature logging project is still running on that same CR2032 battery ever since my original post back in Oct 31st 2012, that makes it 7 months of run time so far.

I have a live chart here:

Funky+DS18b20 on a CR2032

It is probably at the end of its life, but having said so, probably will kick for a month at least. Amazing stuff.

My other project – Funky+DHT22 is also still running on the original AAA battery, it is located outside and has the purpose of logging outside relative humidity and temperature.

Here are the readings for the period:




11 thoughts on “7 months of sending and still going

  1. dzach

    Interesting curves, especially the humudity one, which seems to be saturated most of the time. I was wondering whether there is an opening in the black plastic housing of the Funky+DHT22 to allow air circulation.

    1. Martin Post author

      it is very humid around here, especially the winter months. Yes, the box has a large opening on the bottom to allow circulation, I milled that later. Also, the DHT22 isn’t the most precise sensor too, but a good price/quality ratio.

  2. dzach

    I’ve got two of these installed in Stevenson screens outdoors, but even when raining right on top of them I see only about 80% humidity, so this much saturation is kind of a surprise. This time of the year the average here less than 50%, July and August even dryer.

    1. Martin Post author

      Yes, lovely Greece climate 🙂 Being your northern neighbor gives us slightly more humidity, but you are right that it is unrealistic to have so much of the 99.99% humidity readouts.. I may need to re-consider the boxing as the current one may cause condensation of some kind and hence the such readings

  3. dzach

    Yes, we’ve got that. But it always comes with a fear that the water might not be enough at some point in future. Last years though seem to disprove the desertification theories,, but it may be too early to tell.

    I’ve got two spare 3D printed Stevenson screens, with an inner clearance of 25 and 35mm. I would love to put one into an envelop and send it to you, as a small token of appreciation for the open source work you do. I think the 35mm one would be a good fit, leaving enough space around it. I just need a post address.

  4. Paul Tanner

    I was thinking of setting up an (indoor) temperature sensor or 3 based on Funky+DS18B20 and modifying the sketch in a RFM12pi module (which is already sending Kaku commands) so it would also receive from the temperature sensors.
    – Did you try this?
    – Any reason why it might not work
    Thx. Paul

    1. Martin Post author

      Sending KAKU commands will only temporary disable the receive mode of the RFM12b (while you send), so it is possible to miss a packet. But then “so what”, sending temperature every 5 minutes is working nicely for me, missing a transmission or so doesn’t really matter as room temperature variations aren’t that sudden anyway.

      how often do you intend to send Kaku-s?

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