Mike, I dont get this; I think I understand the setup you describe, but the
glass tube, with or without water, would be transparent, right? how would
you determine the presence of water at a certain point in the tube?

Do you think you could share some more information about your design?

Regards,

Anand Dhuru

----- Original Message -----
From: "Mike Hord" <gaidinmd@HOTMAIL.COM>
To: <PICLIST@MITVMA.MIT.EDU>
Sent: Monday, May 19, 2003 7:25 PM
Subject: Re: [OT] Material that floats in water, yet withstands heat


> It's actually a pretty simple problem to detect a change in an IR light
> source; I'm working on a similar project now that uses a reflected beam.
>
> Pulse the beam with a square wave (a 555 timer will do this nicely), set
up
> a receiver, high pass filter that signal to remove noise from local AC
> sources, then use some sort of switching IC (I'm using the ADG419) to
> demodulate the signal, low pass filter the output to remove harmonics and
> add a gain stage and offset stage to set the levels.  It could probably be
> even simpler than that for an on/off type switch, but just as an idea set,
> there you go!  My current design would work admirably for your usage, and
it
> has six IC's at about $10 total price.
>
> Mike H.
>
>
> >From: Anand Dhuru <ardhuru@VSNL.COM>
> >Reply-To: pic microcontroller discussion list <PICLIST@MITVMA.MIT.EDU>
> >To: PICLIST@MITVMA.MIT.EDU
> >Subject: Re: [OT] Material that floats in water, yet withstands heat
> >Date: Mon, 19 May 2003 16:31:03 +0530
> >
> >Marco., thats a great URL; thanks.
> >
> > >
> > > OK, but there is nothing to stop you shining your light through the
tube
> > > (assuming it is a clear tube) to look for the meniscus of the water.
You
> >do
> > > not need a float.
> >
> >Alan, the tube is indeed transparent; glass. How can the meniscus be
> >detected?
> >
> >I'm still looking at the different possibilities.
> >
> >Regards,
> >
> >Anand
> >
> >
> > >
> > > --
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> > >
> >
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