[IR-L] soil moisture sensors for continuous automatic datalogging

[Albie Cilliers <eilandia@INTEKOM.CO.ZA>]

[Apologies for cross-posting. Bruce]

Albie Cilliers <eilandia@INTEKOM.CO.ZA> writes:

Hi to all,

I recently invested in an Adcon Telemetry automatic weather station.
I'd very much like to attach a soil moisture sensor to it as well, as it
has some spare inputs for extra sensors.  I have heard Adcon developed a
similar kind of sensor like the Sentek Enviroscan probe in conjunction with
a third party and that it is already installed in some systems in South
Africa and perhaps elsewhere in the world as well.

Unfortunately I can't find any info on this new sensor and Adcon's website
is updated so infrequently that I  didn't get any help there either.
Apparantly though, the sensor is going to cost quite a lot and you have to
buy a separate transceiver  (Addit) to be able to send the data to the
central receiver.  (Isn't this typical of companies bringing out new
products which must use another one of their existing products to boost its
slugish sales?)

I therefore are looking for any capable type  of sensor which will be useful
for my purposes and are cost effective.

For me to be able to use such a  sensor, I need the following information:

- Can it operate with a supply voltage of 5.5 to 15 volts ?

- What is the power consumption ?  (<20 mA)

- The sensors output range should be between 0 to 2.5 volts (linear or
  non-linear)

- The reaction time from the moment when the power supply is applied
  until the sensor deliver a valid output should not exceed 2 seconds

- The cabling and connector plug used, as well as the  wire used by the
   sensor in the plug.

- If linear, what is the min and max values ( volts and corresponding
  values) ?
  If nonlinear, can you provide me the sensors variation table?

- Lastly, what would be the cost of such a sensor?

I want to use the sensor for optimally scheduling irrigation for quality
wine grape production in sandy soils using drip irrigation.


I'd really appreciate it if anyone can give me  information on such
products, and if the
sensor can be used (have been used before) in the Adcon weather station, and
also whether there is  a South African agent or distributor.

Thanks
Albie Cilliers