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Sowacs : Two items of interest today, but first,
If anyone has been unsubscribed from sowacs and had to
resubscribe themself recently, please let me know so we can
correct the problem. Thanks, Bruce@icfr.unp.ac.za
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1/ A new water related URL called INTERWATER - (Water Supply and
Environmental Sanitation Electronic Network for Developing
Country Needs) can be found at:
http://www.ccwr.ac.za/interwater/index.html
of which the KwaZulu Natal Water Research Network is of
particular interest being close to [my] home:
http://www.ccwr.ac.za/waternet/
---------------
2/ Romain Gagnon, President of Smart Rain Corporation has sent
through news of his interesting irrigation control system
detailed to some extent on the web page:
FDR/TDR?
The sensor used in the system "based a novel world wide patented
soil moisture, salinity and temperature sensor" looks very much
like a TDR sensor, and the technical detail indicates that it is
some variation on this theme.. Sure enough - on consulting the
excellent complete list of FAQ (66k)
[http://www.SmartRain.com/all.htm] the sensor is described as an
FDR - frequency domain sensor. A lot of the info here is taken
from this page.
COST?
US$300 per sensor (about $10000 for an entire (large) golf course
setup).
The question I have is - can this sensor be used with other
analog loggers?
FERTILISER
By separately measuring the soil water content from the
permittivity (dielectric constant of water), and then the
conductivity, an indirect inference of fertiliser levels is made
by the sensor. It has a temperature sensor built in too, which,
presumably corrects the other measurments (in addition to enable
warning the user of high and low temperature extremes and
possible implications).
An optional Hydraulic pressure tranducer can be added to enable a
water pressure feedback system.
LONWORKS DATA TRANSMISSION
New to me was the concept of using existing power-supply cables
to transmit data! "The data travel both ways through existing
power cables. No need to dig, so you won't disrupt your
landscaping..." "It communicates with the central computer or any
of its peers directly through power lines.."
I had a look to find out more, but wasn't much the wiser after
Netscape crashed at the vital moment ( - OK, I did have 6
sessions running :> )
"Our system is based on LonWorks control technology (see
www.lonworks.echelon.com)."
SOFTWARE TRENDS
The more recent system control software packages appear to be
more powerful and GUI based - meaning that one does need a fairly
powerful PC with Win95 [not to mention 32 MB RAM!:<]. This does
mean that the PC is not dedicated to the system as it can run
background. But it can also mean that the software is less
flexible..
A few more screen grabs, or even a sample download would be the
next logical steps in the development of an already graphic rich
site. cf "Our software is graphical and runs under Windows 95 or
NT."
COMPARE
Fortunately, the page supplies links to their competitors on the
"dare to compare" page:
toro http://www.toro.com/ and
rainbird http://www.rainbird.com/
(who supply similar systems)
The SmartRain system apparently pitches itself at being the best
process control irrigation system - while leaving the actual
irrigating hardware to other companys.
RAINBIRD
The more extensive pages at Rainbird cover many more areas than
just one control system, but I found it difficult to navigate to
the competitor irrigation system for comparison. When I did get
there, there was only a very brief description:
http://www.rainbird.com/rbgolf/products.html
and then I found the software section: "Download demos and find
out what's coming up in the future. Available only to our
distributors and registered users." but which is actually UNDER
CONSTRUCTION, Oh well.. check back later.
TORO
Toro has a lot of basic general info on lawn care, and a short
description of what makes up an automated system under:
http://www.yardcare.com/grasses/faq.watering.html
INCITEMENT?!
As if you didn't need any more incitement to visit the pages,
here's an extract from their web site:
"
NO MORE RAIN SWITCHES. Our Smart Sensor works hard. Buried at
root level, it uses a stainless steel probe coupled with a new
patent-pending electromagnetic principle to measure permittivity
and bulk conductivity of the soil and determine thresholds for
watering and fertilizing. It measures hydraulic pressure (via a
4-20 ma input wire), soil temperature, and even power supply
voltage. It will energize the valve solenoid at the watering
station on specified days and hours, and it can withstand and
detect short-circuit or open-circuit conditions. It communicates
with the central computer or any of its peers directly through
power lines, and it is submersible, weatherproof, frostproof,
robust and internally protected against lightning and electrical
surges (even wrong connections). What more could you ask for?"
SPECS
The technical specs page was poor (to someone trying to steal the
patents;> ) but was adequate consisting only of several schematic
layout information, and some superficial specs as part of each.
NOTE
This is intended to be a personal editorial only - for general
information, and is very much my own opinion. It will hopefully
raise some discussion, and will inform. (I think the free
advertising will be well worth any criticisms levelled here.)
The system/sensors are apparently being evaluated as we speak, so
any feedback in this regard will be very welcome either to the
sowacs group or myself.
Regards
-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.
Bruce Metelerkamp SOIL WATER RESEARCH OFFICER
Institute for Commercial Forestry Research,
University of Natal, PO Box 100281
Scottsville, ZA3209
Rep. of South Africa Voice:27 331 62314
E-mail: bruce@icfr.unp.ac.za FAX:27 331 68905
URL http://www.icfrnet.unp.ac.za/~metele
/SoWaCS.html
/RR.html
Host of SoWaCS (Soil Water Content Sensor) Discussion List.
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