AVR-Chat

Besides the ultrasonic sensor there are a number of other methods...

A donut shaped float incorporating a magnet which rides up and down around a
magnetostrictive line. One sends a pulse down the line and measures the
return from the magnetic float location. Very accurate. 

A donut shaped float incorporating a magnet which rides up and down a track
with embedded reed switches.

As has been mentioned, a capacitive strip line.

A weighted float attached to a counterweighted (or spring loaded) cable
which turns an encoder as the float travels up and down. Also very accurate.

Similar to the capacitive sensor, a resistive sensor (for conductive
fluids). The higher the level, the less the resistance.

An air bubbler. Sense the pressure of the air line while slowly bubbling
said line at the bottom of the tank. The sensor could be above the liquid
level so as not to be harmed by a pressure failure.

Etc...

-----------------------------------
Bob Tilden, tilden@northwestern.edu
High Energy Physics Group
Northwestern University

-----Original Message-----
From: AVR-Chat@yahoogroups.com [mailto:AVR-Chat@yahoogroups.com] On Behalf
Of kernels_nz
Sent: Wednesday, May 13, 2009 7:33 PM
To: AVR-Chat@yahoogroups.com
Subject: [AVR-Chat] Re: Sensor

Back when I was at Uni a few years ago, one of the students had a project to
electronically measure the water level in a plastic tank. Best way I have
seen this done is run two parallel metal plates along the depth of the tank
and then look at the change in capacitance between the two plates based on
the amount of water between the plates. As the water level dropped, the
capacitance would decrease because the relative permeability of water is
higher than air . . . (Hope I remembered all this correctly) Set this up as
a oscillator with frequency based on capacitance and you have a varying
output frequency based on the water level.

Hein B
Auckland, New Zealand.

--- In AVR-Chat@yahoogroups.com, "Brian" <blue_eagle74@...> wrote:
>
> I think the best non-movement sensor would be a presure sensor at the
bottom of the tank. No moving parts and it can be sealed. So it could
measure many liquids.
> 
> Brian
> 
> --- In AVR-Chat@yahoogroups.com, Muhammad Amiruddin <amiruddin.muhammad@>
wrote:
> >
> > Dear all,
> >  
> > please help me,
> >  
> > i want make project for measuring the level of water on the tank that
approximately 15 m high. what senssor that i should use ?
> >  
> > Is there any ultrasonic senssor wich can measure range until 15 m ?
> >  
> > rgds,
> >  
> > 4mir
> >  
> > 
> > 
> >       
> > 
> > [Non-text portions of this message have been removed]
> >
>




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