Re: Soil moisture sensors

[MFHult@xxxxxxxxxxxxxxxxxxxxx]

On Mon, 13 Jun 2005 16:52:28 GMT, nobody@xxxxxxxxxxxx (Dave Houston) wrote
in message  <42adb8e0.5618757@xxxxxxxxxxxxx>:

>http://www.emesystems.com/pdfs/SMX.pdf

Aside from minor technical quibbles, this is a very good write-up. The
ever-handy 555 timer circuit is easily built and presumably works.

Note that the tables presented are not the tables provided by Irrometer
with their stated/recommended constant-frequency excitation but rather the
response when using emesystems' 555-based circuit.

Consider 'calibrating' the sensors phenomenologically ("Turn on the water
when the reading reaches x whatevers because at x whatevers, the plants
look thirsty".

HTH ... Marc
Marc_F_Hult