Gypsum Block Sensor

[Bill Pogue]

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Bill Pogue writes:

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Dear Mr. Lu:
Although our Company does not advertise on SOWACS you may be interested in
visiting our website at: www.irrometer.com and look at the Landscape
Catologue to read about the use of our Watermark sensor linked to our
Watermark Electronic Module (WEM).  Essentially the WEM is the switching
interface between the Watermark sensor and any standard "automatic" control
system which utilizes 24VAC to activate solenoid valves.  It is fully
adjustable from 10 to about 125 kPa which would cover the full range of
irrigated ornamental plantings used in the landscape in most soil types.  In
our Newsletter Section you can find a hyperlink to the site of Oregon State
University which discusses the Watermark sensor and provides a list of
references from both agriculture and ornamental horticulture.  If you would
like to communicate with me directly feel free to do so at:
billp@irrometer.com.
Regards, Bill Pogue, President, Irrometer Company, Inc.
----- Original Message -----
From: <owner-sowacs@aqua.ccwr.ac.za>
Sent: Friday, March 01, 2002 12:56 PM
Subject: Gypsum Block Sensor

> Dear all,
>
> I am a student from TUDelft,the Netherlands. My partner and I are doing a
> project which develops a system to water office plants automatically.The
> soil moisture required by the plants can be divided into three levels:
High,
> Medium and Low. In this case, we need a soil moisture sensor to keep on
> monitoring the moisture level of the soil and decide whether to add water
or
> not.
>
> I are thinking of using Gypsum Block Senor, because it is cheap and meet
our
> requirement(we don't need detailed value of soil moisture but certain
ranges
> corresponding to three levels).
>
> What's your suggestion about this selection of Gypsum Block Sensor? Do you
> have any better idea in how to implement this system? Please do not
hesitate
> to let me know.
>
> And I found that there were not so many Gypsum Block Sensors on the
market.
> The famous one may be Watermark. Can I buy it in the netherland? If you
know
> some companies in the netherlands or around sell Gypsum Block Sensor,
please
> tell me as soon as possible.
>
> Best regards,
> weidong LU
>
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> [Bruce comments
> Yes, some sort of electronic switch that is triggered to irrigate when
> certain threshhold resistances values are met would seem a good way to
go...
> I'm sure the irrigaters in the list will suggest how to do this
> in a practical sense?
> Have a look at http://www.sowacs.com/sensors/gypsum.html as well as
> the feature article http://www.sowacs.com/feature/mea/mea.html
> ]
>
>




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