Moisture Meter and the Stamp
Archiver
Posts: 46,084
The simplest solution to measuring the moisture in soil has been to stick
two different metals in the soil and measure the voltage difference with an
ADC. Any circuit that I tried that passed a current through the soil gave a
readings that increased at a fixed rate over time (capacitance of the
soil???). Copper and zinc electrodes seem to work well.
And you ask ?WHY ? is he telling us this.
My project is to have my robot water my plants, so I need the simplest and
quickest method of testing the soil. The water control, as well as the
movement of the robot, has been easy. It is great at finding potted plants,
but sucks in a garden (many trampled flowers), but watering a full garden is
done by a huge supply of water. So it is really the pots that I am trying
to work on.
Matthew
'If you have a problem.....STAMP on it'
two different metals in the soil and measure the voltage difference with an
ADC. Any circuit that I tried that passed a current through the soil gave a
readings that increased at a fixed rate over time (capacitance of the
soil???). Copper and zinc electrodes seem to work well.
And you ask ?WHY ? is he telling us this.
My project is to have my robot water my plants, so I need the simplest and
quickest method of testing the soil. The water control, as well as the
movement of the robot, has been easy. It is great at finding potted plants,
but sucks in a garden (many trampled flowers), but watering a full garden is
done by a huge supply of water. So it is really the pots that I am trying
to work on.
Matthew
'If you have a problem.....STAMP on it'
Comments
The voltage you have measured is a D.C. voltage, O.K.? So in D.C. you have
a polarisation phenomena of dipolar molecules of wet soil in a way that
you´ll have a great trouble in measure voltage or resistance. You must
measure in a.c.
See Earth Measurements Student Guide Version, Exp #5 on Parallax site, and
you will find there a very simple circuit to measure humidity of soil with
A.C. and a Basic Stamp.
cheers
Jorge
Original Message
From: Matthew Lewis <aiden.bell@h...>
To: <basicstamps@egroups.com>
Sent: Saturday, August 12, 2000 2:41 PM
Subject: [noparse][[/noparse]basicstamps] Re: Moisture Meter and the Stamp
> The simplest solution to measuring the moisture in soil has been to stick
> two different metals in the soil and measure the voltage difference with
an
> ADC. Any circuit that I tried that passed a current through the soil gave
a
> readings that increased at a fixed rate over time (capacitance of the
> soil???). Copper and zinc electrodes seem to work well.
>
> And you ask ?WHY ? is he telling us this.
>
> My project is to have my robot water my plants, so I need the simplest and
> quickest method of testing the soil. The water control, as well as the
> movement of the robot, has been easy. It is great at finding potted
plants,
> but sucks in a garden (many trampled flowers), but watering a full garden
is
> done by a huge supply of water. So it is really the pots that I am trying
> to work on.
>
> Matthew
>
> 'If you have a problem.....STAMP on it'
>
>
>