Mads, I prefer RF impedance measurements of total available water over the old tension or gypsum systems. This is where the research community has moved. My problem with the older technology is that it measures the instantaneous water availability rather than the soil stored water. You really want to know if you will have enough water for the next day if you don't irrigate now, and water capacity is a better measure of that. With the high frequency model, they are both volume and salinity insensitive, what you need for your pot measurements. They also read in 1-2 seconds, which is nice if you want to move them for a quick reading.
The cheapest ones I have found are vegatronix (http://vegetronix.com/Products/VH400/) at $37 each. They are a 3.3-20V drive and 0-3v out with published curves, so it should take very little to connect them up to a 1-wire voltage reader and apply the curves in software. You can even read them off a multimeter. With any of these, you have to still learn a bit about your soil, climate and plants to understand how to turn a reading into a meaningful decision. 25% water volume could be 2 days worth or not make it a day depending on soil, climate and plant demand. jerry On 03/17/2012 06:13 AM, Mads Hjorth wrote: > Dear list, > > I realize this might be slightly off topic. Feel free to point me to a better > forum if you know one. > > What is the best sensor to get a reading of water content / soil moisture > into owfs? > > I have been trying to use a WATERMARK 200SS-V sensor with a DS2438, but ended > up realizing the sensor is not suitable for flower pots. > > Anybody had any success with soil moisture and owfs? > > Thanks, > > Mads > > ------------------------------------------------------------------------------ > This SF email is sponsosred by: > Try Windows Azure free for 90 days Click Here > http://p.sf.net/sfu/sfd2d-msazure > _______________________________________________ > Owfs-developers mailing list > Owfs-developers@lists.sourceforge.net > https://lists.sourceforge.net/lists/listinfo/owfs-developers ------------------------------------------------------------------------------ This SF email is sponsosred by: Try Windows Azure free for 90 days Click Here http://p.sf.net/sfu/sfd2d-msazure _______________________________________________ Owfs-developers mailing list Owfs-developers@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/owfs-developers
