Re: Automatic flushers

[Bernard Cleyet <anngeorg@PACBELL.NET>]

Thank you; saved my hunting down my dead sprinkler valve (rubber diaphragm holed -- no
replacement easily available)  About the problem of changing condix, etc.  I think the
principal method is the use of the IR filter;  for passers by the integrator does it, as
already mentioned below.

bc



Michael Edmiston wrote:

> * * * * with regard to diaphragm valves * * * *
>
> I have made a drawing and have included some text to show how a diaphragm
> valve works.  There are several variations of this, but my drawing and
> explanation should get the idea across.
>
> My drawing and text are in an Adobe Acrobat PDF file.  Since we're not
> supposed to put attachments on e-mails to the list, I put this file on my
> root directory of our Internet server.  I am way behind times getting a
> personal web page set up... I just don't have the time.  But you can get in
> your browser and get this PDF file by using the following URL.
>
> www.bluffton.edu/~edmistonm/diaphragm.valve.pdf
>
> * * * * with regard to IR actuators * * * *
>
> William Beaty's description of smart sensors using a microprocessor unit was
> interesting.  I am not sure that any smart units are available powered by
> batteries; I would guess perhaps not because battery life could be short.
>
> The units we installed in a new building on campus are indeed battery
> operated, and I would guess they are not very "smart."  It does not require
> a microprocessor to avoid random flushing by passers-by, or by changes in
> ambient light, etc.  There are a variety of ways to do this.  By using some
> combination of integration or differentiation of the photo-detector signal
> via simple operational-amplifier circuitry followed by simple digital logic,
> the unit can be made immune to drifting light levels (ambient light changes)
> and immune to quick changes (passers-by).  A sustained significant increase
> in detector signal (for a second or two), followed by a sustained
> significant decrease in detector signal can actuate the valve.  This can be
> done with very low-power op-amps and logic circuits that could easily run
> several months on a battery.
>
> This new building also uses key-cards with magnetic strips like those used
> in hotels.  These also operate from batteries, and battery life is said to
> be about a year.
>
> Michael D. Edmiston, Ph.D.              Phone/voice-mail:       419-358-3270
> Professor of Chemistry & Physics        FAX:                    419-358-3323
> Chairman, Science Department            E-Mail                  edmiston@bluffton.edu
> Bluffton College
> 280 West College Avenue
> Bluffton, OH 45817