yet more Prox sensor info
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Probably wont be able to use any sort of optical or mechanical switch due to
the nature of the substance.....very corrosive, tend to stick to surfaces,
dusty at times.
Stocky
Original Message
From: <scottsmith13@a...>
To: <basicstamps@yahoogroups.com>
Sent: Friday, July 06, 2001 4:43 PM
Subject: Re: [noparse][[/noparse]basicstamps] Prox sensor
> A pretty standard IR LED proximity pair would potentially work. You would
> need to set the sensor back into the tube a bit and use a window that does
> not reflect so much to be read. The concern would be that the window
surface
> would become abraded or dusty and give a false positive. How far is the
> distance across the silo where you want to measure? If it is near an
> constriction, you may be able to put a separated pair and shoot from one
side
> to the other.
>
> If there is normally light inside the silo then a photovoltaic cell would
> potentially work.
>
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Body of the message will be ignored.
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>
the nature of the substance.....very corrosive, tend to stick to surfaces,
dusty at times.
Stocky
Original Message
From: <scottsmith13@a...>
To: <basicstamps@yahoogroups.com>
Sent: Friday, July 06, 2001 4:43 PM
Subject: Re: [noparse][[/noparse]basicstamps] Prox sensor
> A pretty standard IR LED proximity pair would potentially work. You would
> need to set the sensor back into the tube a bit and use a window that does
> not reflect so much to be read. The concern would be that the window
surface
> would become abraded or dusty and give a false positive. How far is the
> distance across the silo where you want to measure? If it is near an
> constriction, you may be able to put a separated pair and shoot from one
side
> to the other.
>
> If there is normally light inside the silo then a photovoltaic cell would
> potentially work.
>
> To UNSUBSCRIBE, just send mail to:
> basicstamps-unsubscribe@yahoogroups.com
> from the same email address that you subscribed. Text in the Subject and
Body of the message will be ignored.
>
>
> Your use of Yahoo! Groups is subject to http://docs.yahoo.com/info/terms/
>
>
Comments
This technology isn't cheap, but has it's merits...
(quantum capacitance sensors)
http://www.qprox.com/
Ken
with enough thrust, pigs fly just fine.
---- On Fri, 6 Jul 2001, Tim Stockman, STOCKMAN ELECTRONICS
(stocky@c...) wrote:
> Probably wont be able to use any sort of optical or
mechanical switch
> due to
> the nature of the substance.....very corrosive, tend to stick
to
> surfaces,
> dusty at times.
>
> Stocky
>
Original Message
> From: <scottsmith13@a...>
> To: <basicstamps@yahoogroups.com>
> Sent: Friday, July 06, 2001 4:43 PM
> Subject: Re: [noparse][[/noparse]basicstamps] Prox sensor
>
>
> > A pretty standard IR LED proximity pair would potentially
work. You
> would
> > need to set the sensor back into the tube a bit and use a
window that
> does
> > not reflect so much to be read. The concern would be that
the window
> surface
> > would become abraded or dusty and give a false positive.
How far is
> the
> > distance across the silo where you want to measure? If it
is near an
> > constriction, you may be able to put a separated pair and
shoot from
> one
> side
> > to the other.
> >
> > If there is normally light inside the silo then a
photovoltaic cell
> would
> > potentially work.
> >
> > To UNSUBSCRIBE, just send mail to:
> > basicstamps-unsubscribe@yahoogroups.com
> > from the same email address that you subscribed. Text in
the Subject
> and
> Body of the message will be ignored.
> >
> >
> > Your use of Yahoo! Groups is subject to
> http://docs.yahoo.com/info/terms/
> >
> >
>
>
> To UNSUBSCRIBE, just send mail to:
> basicstamps-unsubscribe@yahoogroups.com
> from the same email address that you subscribed. Text in the
Subject
> and Body of the message will be ignored.
>
>
> Your use of Yahoo! Groups is subject to
> http://docs.yahoo.com/info/terms/
>
>
>
>
Check out quantum capicatance devices at
http://www.qprox.com/
Ken
with enough thrust, pigs fly just fine.
---- On Fri, 6 Jul 2001, Tim Stockman, STOCKMAN ELECTRONICS
(stocky@c...) wrote:
> Probably wont be able to use any sort of optical or
mechanical switch
> due to
> the nature of the substance.....very corrosive, tend to stick
to
> surfaces,
> dusty at times.
>
> Stocky
>
Original Message
> From: <scottsmith13@a...>
> To: <basicstamps@yahoogroups.com>
> Sent: Friday, July 06, 2001 4:43 PM
> Subject: Re: [noparse][[/noparse]basicstamps] Prox sensor
>
>
> > A pretty standard IR LED proximity pair would potentially
work. You
> would
> > need to set the sensor back into the tube a bit and use a
window that
> does
> > not reflect so much to be read. The concern would be that
the window
> surface
> > would become abraded or dusty and give a false positive.
How far is
> the
> > distance across the silo where you want to measure? If it
is near an
> > constriction, you may be able to put a separated pair and
shoot from
> one
> side
> > to the other.
> >
> > If there is normally light inside the silo then a
photovoltaic cell
> would
> > potentially work.
> >
> > To UNSUBSCRIBE, just send mail to:
> > basicstamps-unsubscribe@yahoogroups.com
> > from the same email address that you subscribed. Text in
the Subject
> and
> Body of the message will be ignored.
> >
> >
> > Your use of Yahoo! Groups is subject to
> http://docs.yahoo.com/info/terms/
> >
> >
>
>
> To UNSUBSCRIBE, just send mail to:
> basicstamps-unsubscribe@yahoogroups.com
> from the same email address that you subscribed. Text in the
Subject
> and Body of the message will be ignored.
>
>
> Your use of Yahoo! Groups is subject to
> http://docs.yahoo.com/info/terms/
>
>
>
>
>> I am looking for a circuit that will be suitable to detect the
>>presence of a granular fertilizer in a storage silo. Just need a
>>go/no-go type output eg whether the sensor is covered or not.
>Hi,
> This technology isn't cheap, but has it's merits...
>(quantum capacitance sensors)
>http://www.qprox.com/
>Ken
I'll second Ken's suggestion, from personal experience with Qpox
chips. But as to expensive, you might get by with the QT114 level
sensor IC (8-pin dip or SOIC), which runs about $2.50 for the chip or
$15 for the demo board. The company specs it for "limit sensing of
almost any fluid or powder", although it would work best if the
fertilizer is somewhat conductive. Their more expensive QT9701 is
highly programmable and requires a development kit. Quantum is an
English company, so they should have a good outlet in Australia.
Also visit
http://www.sensorsmag.com
and look at the article index. There is a level sensing article
online from Oct. 2000, others too, and links through globalspec. I've
seen ads in there for some exotic powder sensing technologies. E.g.
vibrations of a probe put through the side of the tank. Vibration is
damped when powder is present.
-- regards,
Tracy Allen
electronically monitored ecosystems
mailto:tracy@e...
http://www.emesystems.com
>the nature of the substance.....very corrosive, tend to stick to surfaces,
>dusty at times.
I solved similar problems once or twice with a simple capacitive sensor...
Drive a capacitive probe with a square wave, through a resistor. Feed the
signal at the probe, and the signal upstream of the resistor, to an XOR
gate (serves as a phase detector). Integrate the XOR output with a simple
RC network. The result (after you fiddle with the circuit values a bit) is
a DC voltage proportional to capacitive loading on the probe. Just add a
voltage comparator to get your YES/NO logic output.
Mike Hardwick, for Decade Engineering -- <http://www.decadenet.com>
Manufacturer of the famous BOB-II Serial Video Text Display Module!
a motorized shaft with a small plate of metal on the inside end of the shaft.
(Inside of silo)
The sensor is designed "Know" if the paddle can turn or not. If the material
has reached the paddle it cant turn. These can be rather expensive. There are
sensor of the capacitive type that would work just fine. Almost anything near
them can be detected. If you need some more detail let me know. I have several
catalogs with sensors in them. If this has been mentioned please ignore.
I lost all my e-mail recently!!
kd
"Tim Stockman, STOCKMAN ELECTRONICS" wrote:
> Probably wont be able to use any sort of optical or mechanical switch due to
> the nature of the substance.....very corrosive, tend to stick to surfaces,
> dusty at times.
>