Pressure transducers and basic stamps...
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I'm part of an advanced robotics class that's undertaken the task of
monitoring the flow of water in a stream or river. We're just getting
started on this project and need a little help; a few questions and
that's all :-). First of all the components we will be using are: A
Basic stamp, a pressure transducer, some form of external power, a
clock chip, and extra memory (probably EEPROM). The questions we have
are: for this project which basic stamp should be used, which make
and model pressure transducer to use, and if you think EEPROM will
work.
This whole unit will be placed in a water proof container, weighted,
and set at the bottom of a river/stream with batteries and more then
likely a hydro-electric generator as a backup. So the first goal is
to measure the height of the water during a rain storm, and
the second goal is to have enough battery power and memory so it
won't have to be checked that often.
If anybody thinks they can help, or if I've left some information
out
please E-mail me. Any help we can get would be greatly appreciated.
Eryk
monitoring the flow of water in a stream or river. We're just getting
started on this project and need a little help; a few questions and
that's all :-). First of all the components we will be using are: A
Basic stamp, a pressure transducer, some form of external power, a
clock chip, and extra memory (probably EEPROM). The questions we have
are: for this project which basic stamp should be used, which make
and model pressure transducer to use, and if you think EEPROM will
work.
This whole unit will be placed in a water proof container, weighted,
and set at the bottom of a river/stream with batteries and more then
likely a hydro-electric generator as a backup. So the first goal is
to measure the height of the water during a rain storm, and
the second goal is to have enough battery power and memory so it
won't have to be checked that often.
If anybody thinks they can help, or if I've left some information
out
please E-mail me. Any help we can get would be greatly appreciated.
Eryk
Comments
I guess the place to start is the pressures involved.
at around 33 ft depth, the water pressure is about 14.7 psi. water
density will change with what is in the water. salt water will be
different than fresh, particulate will change things too.
All pressure sensors are differential in their basic design.
usually, one side is to the reference and the other to the process.
in your case, a submerged unit will need some form of second chamber
as the water will be the primary..
My first thought is to use a piezoelectric sensor as the unit has no
movement. Maybe someone on the list will offer some detail on using
such a device ?
The idea of the unit generating it's own power is cool, but I'm not
sure of the best way that would take in account debris.
read up on sleep mode as you do not need to monitor at very rapid
rates. also, do not expect great results in shallow water. the
deeper you go, the better the readings will be as the span of the
device is important. get over 20% and shoot for a maximum of 80% of
span. don't try to just amplify the reading as it will be mostly
amplifying errors. pressure sensors are notorious for being error
prone.
IF you are measuring flow and not pressure then you need to get a
very sensitive unit. the velocity pressure of flow is a minute
pressre compared to the static pressure. That is why most people use
turbines or paddle wheels to measure flow. and that is easy. a
propeller with a method of knowing when a blade has passed. just
count speed of the propeller, or connect it to a motor and let the
motor act as a generator, then measure voltage.
Dave
--- In basicstamps@yahoogroups.com, "bgrobotics <Air_force@w...>"
<Air_force@w...> wrote:
> I'm part of an advanced robotics class that's undertaken the task
of
> monitoring the flow of water in a stream or river. We're just
getting
> started on this project and need a little help; a few questions and
> that's all :-). First of all the components we will be using are:
A
> Basic stamp, a pressure transducer, some form of external power, a
> clock chip, and extra memory (probably EEPROM). The questions we
have
> are: for this project which basic stamp should be used, which make
> and model pressure transducer to use, and if you think EEPROM will
> work.
>
> This whole unit will be placed in a water proof container,
weighted,
> and set at the bottom of a river/stream with batteries and more
then
> likely a hydro-electric generator as a backup. So the first goal is
> to measure the height of the water during a rain storm, and
> the second goal is to have enough battery power and memory so it
> won't have to be checked that often.
>
> If anybody thinks they can help, or if I've left some information
> out
> please E-mail me. Any help we can get would be greatly appreciated.
>
> Eryk