Artifact

Here’s today’s graph.  As suggested, I found a way to mark the average temperature (57.6º)– doing that also colored the background (pink above average, blue below) which is a little annoying.

Of technical interest– I discovered a data artifact that was causing some false elevation in past graphs.  Often the graph showed a substantial spike during periods when I was standing at the kitchen counter, typing on my (half-frozen) laptop, about four feet away from the datalogger  (you can see one of these blips the graph above, at 8pm).  For a while I attributed this to body heat affecting the device, and tried moving further and further away– but the effect persisted.  Finally last night, with some experimentation, I found that it was the datalogger itself producing the heat– when connected via its cord to the laptop USB, it seems to warm itself by 2-3º until unplugged.  Doh!  (It isn’t charging at these times– it has a standard battery– it must just be… thinking hard…)  So, no more leaving the datalogger plugged in while I’m puttering.

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4 Responses to “Artifact”

  1. Pop Says:

    I like the pink. Can’t see the line for the average, if there is a line.

    Regarding the blip, this sounds like Heisenberg’s Uncertainty Principle.

  2. coldhousejournal Says:

    The line is just sort of a white line… at the junction of the pink & the blue. Not ideal… working on finding a better way. And yes– it is very much like the Uncertainty Principle! Problematic. But the datalogger only really needs to be plugged in for about 30 seconds to download the data, so it can be minimized.

  3. John Says:

    Clearly it’s color-coded for skin, right? Blue in the cold, pink in the heat. 🙂

    On the sensor’s heating issues, maybe you should move it to a place where there’s no overhanging edge to trap the rising warm air generated by the charging process. Try putting it on the countertop while it charges and see what happens. Or move it further down the side, away from the overhang.

  4. John Says:

    Oops, not charging process, but presumably waste heat from current via the USB cable.

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