On Sun, May 02, 2010 at 12:45:44PM -0700, Marc MERLIN wrote: > current board temp (F) > wet icy: -1.13 70.475 > wet ambiant: -1.3825 70.025 > wet warm: -1.72063 70.7 > > I suppose the fact that humidity probes vary with temps is not new, but > the moisture probe doesn't seem temp corrected at all (not even the board > measured temp in case I was going to burry the board with the sensor to get > soil temp). > > I realize that soil temperatures don't vary as extremely as in my water glass > case, but dirt that is getting warmer and dryer giving a constant current > reading for a while as rising temp cancels out lowering humidity, is not too > ideal. > > Do you think it would be doable to make a moisture reading that is more or > less temperature corrected, at least using the temp seen on the board?
Putting this aside for now, as soon as I burried the sensor, it stopped working (it just jumps back and forth between values): Sun May 2 21:33:59 PDT 2010 -0.150625 61.475 Sun May 2 21:34:09 PDT 2010 -0.169375 61.475 Sun May 2 21:34:19 PDT 2010 -0.169375 61.475 Sun May 2 21:34:29 PDT 2010 -0.24125 61.475 Sun May 2 21:34:39 PDT 2010 -0.24125 61.475 Sun May 2 21:34:49 PDT 2010 -0.133125 61.475 Sun May 2 21:34:59 PDT 2010 -0.133125 61.475 Sun May 2 21:35:09 PDT 2010 -0.14875 61.25 (...) Sun May 2 21:41:57 PDT 2010 -0.143125 61.25 Sun May 2 21:42:07 PDT 2010 -0.14875 61.25 Sun May 2 21:42:20 PDT 2010 -0.14875 61.25 Sun May 2 21:42:30 PDT 2010 -0.12 61.25 Sun May 2 21:42:43 PDT 2010 -0.12 61.25 Sun May 2 21:42:53 PDT 2010 -0.155625 61.25 This is disappointing, it was reported to Eric over a year ago, and the problem is still there in new boards being sold today. I'm pasting the results of my search here for the sake of the archives and other people searching: http://www.cocoontech.com/forums/index.php?showtopic=12330 There seems to be a ground loop problem and apparently the fix is to buy an isolation transformer: https://www.photonage.com.au/600-ohm-600-ohm-potted-telephone-isolation-transformer-p-7600.html but I now need to find a suitable one I can order in the US. Unfortunately, adding this will also invalidate all my range tests before I dug in the sensor. I'm not really looking forward to undigging all this :( I'll ask Eric to see why if it's a known problem it's still not fixed in the current shipping versions and why there seems to be no notice of this problem on http://www.hobby-boards.com/catalog/howto_moisture_meter.php?referer=howto_humidity_temp_solar.php Marc -- "A mouse is a device used to point at the xterm you want to type in" - A.S.R. Microsoft is to operating systems & security .... .... what McDonalds is to gourmet cooking Home page: http://marc.merlins.org/ ------------------------------------------------------------------------------ _______________________________________________ Owfs-developers mailing list Owfs-developers@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/owfs-developers
