Vegie Garden Moisture Monitor

["Frank Mc Alinden" <frankmc@xxxxxxxxxxxxxxxx>]

Hi Guys

After installing Gerry Dupreys jSprinkler system in my small vegie patch
and which has been running fine for quite a while now i decided to have a
go at monitoring each vegie zones soil moisture. I initially had a play
with using a sensor circuit connected to a DS10 device but thought that
since my vegie patch is quite small a dedicated controller might be the
best option....I scoured the net for a suitable solution without any
luck..I did come across a project which i used the same method of sensing
the soil moisture...

http://www.rgbled.org/sprinkler/index.html

http://www.bookcracker.com/projects/M278.html

For the controller i decided to use the same hardware that i use for my
vegie sprinkler system which uses a pic16F877as the brains...This board
sells for around $25 U.S. from futurelec...This device has lots of i/o and
i was specially interested in the 8 analog inputs which im using as
moisture inputs..

http://www.futurlec.com/PIC16F877_Controller.shtml

For the sensing probes i use some clipsal plastic conduit fittings , a 25mm
coupling ,2 25mm end caps, 2 160mm long stainless steel 3mm threaded rod
and a 3mm Bicoloured led and some 4 core security cable....The threaded rod
is covered in clear heatshrink exposing the last 10 mm so that hopefully
will give truer reading at root level...

I was looking around the net for some sample pic code asm or picbasic to
get me started when i came across a link to an app which allows you to
program pics or avr,s in PLC Ladder logic.. Afer some help from the author
(jonathon) i got the board working reading a couple of probes that i had
setup in pots for testing. The only issue i had was that i had to drop the
baudrate on the serial connection as in recieve mode the board couldnt keep
up when running at 9600/4800 baud so for reliable operation the baud was
set at 2400....

http://cq.cx/ladder.pl

The board responds to queries from a host controller using a simple ascii
protocol...To query zone 1 the host sends the following QAx.......which
means it would like to Query Analog x ( 1 to 8) ...The Controller then
replys val=xxxx were xxxx can be 0000 to 1023....

Since i use xPL and my Sprinkler system is controlled by xPL i thought it
would be nice if i coulkd use xPL to control it...Not being a software
programmer i made a request on the xPL Forum and luckily Mal Lansell (
xpl-rfxcom Guru) came to my rescue..So now using Mals app along with
another xPL app xPL-Timer i am polling the probes once an hour
with 3 minutes intervals between each probe reading....I have a recurring
event which trigger once every hour requesting zone 1 data..the controller
reply triggers a 3 minute timer which will time out and request zone 2 data
and this triggers zone 3 timer etc....

http://www.xplmonkey.com/
http://xplproject.org.uk/?page_id=2

Im not sure how successful this project is going to be , its early
days..i,ll record the probes reading over the next few weeks and see if i
can make sense of it ...If it does work out reasonably well i think i might
have a go at making a pic interface to a DS10 device so i can use rf
versions on my garden beds....
Some pics of my Moisture kit
http://s195.photobucket.com/albums/z38/fra...ture%20Monitor/

Frank

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