Searching \ for '[OT]: Fountain Project- Help Me Pick A Sensor' in subject line. ()
Make payments with PayPal - it's fast, free and secure! Help us get a faster server
FAQ page: www.piclist.com/techref/microchip/ios.htm?key=sensor
Search entire site for: 'Fountain Project- Help Me Pick A Sensor'.

No exact or substring matches. trying for part
PICList Thread
'[OT]: Fountain Project- Help Me Pick A Sensor?'
2006\04\09@050921 by Bob Axtell

face picon face
My wife bought a ceramic fountain. It has a pump that draws water
from the bottom and pumps it to the top, so the birds can bathe in it
and it srips down to the bottom again. Looks neat, works nice, kills
some of the road noise.

The problem is that in So Arizona, the water evaporates so fast, I
can't discipline myself to keep it filled. So... I am gonna design a
slick way to sense when the water level is low so it can kick on a
solenoid and pump some back into it. I don't want to use anything
ugly, or big (like a float valve). I had in mind a  non-contact sensor,
perhaps a capacitor. The whole sensor/solenoid deal could then
be automatic.

What would work reliably? I am leaning toward a probe with two
insulated contacts, that I can make part of a tuned circuit; when
the water is missing between the probes, the frequency is at a
certain range, with the water between the probes, the frequency
is detuned. Another idea was to mount a  tiny magnetic float  in
a plastic tube, and when the  float  is high enough, it triggers a
hall device.

Any other ideas? Lotsa talent here. I have piles of PICs, can always
help control the solenoid that way...

--Bob

--
Note: To protect our network,
attachments must be sent to
spam_OUTattachTakeThisOuTspamengineer.cotse.net .
1-520-850-1673 USA/Canada
http://beam.to/azengineer

2006\04\09@052832 by Jinx

face picon face
Bob, three gold-plated wires would do as a simple SPST switch. If
#2 is 1" longer than #1 and #3 is 1" longer than #2 you have a switch
with #2 as the common. The end of #1 is at the high water mark. If
level falls below #2, then #2 and #3 are not shorted and the pump
turns on. When water shorts #1 to #2 it turns off

You could make them very fine, even colour them the same as the
fountain so they'd not be too obvious

2006\04\09@100953 by Bob Axtell

face picon face
Jinx wrote:

>Bob, three gold-plated wires would do as a simple SPST switch. If
>#2 is 1" longer than #1 and #3 is 1" longer than #2 you have a switch
>with #2 as the common. The end of #1 is at the high water mark. If
>level falls below #2, then #2 and #3 are not shorted and the pump
>turns on. When water shorts #1 to #2 it turns off
>
>You could make them very fine, even colour them the same as the
>fountain so they'd not be too obvious
>
>  
>
Jinx, that looks pretty good! Use AC, i.e. 12VAC, so the wires won't be
eaten away?
and the currents would be small...and it just means only 3 wires to bury.

I like it.

--Bob

--
Note: To protect our network,
attachments must be sent to
.....attachKILLspamspam@spam@engineer.cotse.net .
1-520-850-1673 USA/Canada
http://beam.to/azengineer

2006\04\09@102238 by Jinx

face picon face
> Use AC, i.e. 12VAC, so the wires won't be eaten away ?

Yes, if you can. I made an electric fence to keep snails out of the
veges. It was a border of upright 6" planks with two wires around,
1/2" apart. Originally I had 12V and 0V but the wire, even though
it was galvanised, corroded quite quickly. I replaced it and switched
to AC and had no more problems. A couple of seasons later I had
to do the same to a location not within easy reach of power, so it
had to run off a battery. I made a retriggerable one-shot driving a
trigger transformer. 5ms every 5s as I recall. Worked just as well
and 4 * D batteries lasted a very long time

2006\04\09@114923 by Danny Sauer

flavicon
face
Bob wrote regarding '[OT]: Fountain Project- Help Me Pick A Sensor?' on Sun, Apr 09 at 04:12:
> can't discipline myself to keep it filled. So... I am gonna design a
> slick way to sense when the water level is low so it can kick on a
> solenoid and pump some back into it.

The ultrasonic ("cold mist") humidifiers I've had all use a single
piece of wire that senses water.  I think similar things are used for
detecting leaks in places like server rooms and basements.

Kinda like what these people make and sell:
http://www.rletech.com/products/waterdetection.html

That might be something to further research - maybe just how those
things work... :)

--Danny

2006\04\09@120847 by blackcat

face picon face
Could be using TDR ( time domain reflectometry )
example:   http://www.tscm.com/tdr.html
water causes short

POD

On 2006-Apr 09, at 9:49 AM, Danny Sauer wrote:

Bob wrote regarding '[OT]: Fountain Project- Help Me Pick A Sensor?'  
on Sun, Apr 09 at 04:12:
> can't discipline myself to keep it filled. So... I am gonna design a
> slick way to sense when the water level is low so it can kick on a
> solenoid and pump some back into it.

The ultrasonic ("cold mist") humidifiers I've had all use a single
piece of wire that senses water.  I think similar things are used for
detecting leaks in places like server rooms and basements.

Kinda like what these people make and sell:
http://www.rletech.com/products/waterdetection.html

That might be something to further research - maybe just how those
things work... :)

--Danny

2006\04\09@123458 by Gus Salavatore Calabrese

face picon face

Could be using TDR ( time domain reflectometry )
example:   http://www.tscm.com/tdr.html
water causes short

POD

On 2006-Apr 09, at 9:49 AM, Danny Sauer wrote:

Bob wrote regarding '[OT]: Fountain Project- Help Me Pick A Sensor?'  
on Sun, Apr 09 at 04:12:
> can't discipline myself to keep it filled. So... I am gonna design a
> slick way to sense when the water level is low so it can kick on a
> solenoid and pump some back into it.

The ultrasonic ("cold mist") humidifiers I've had all use a single
piece of wire that senses water.  I think similar things are used for
detecting leaks in places like server rooms and basements.

Kinda like what these people make and sell:
http://www.rletech.com/products/waterdetection.html

That might be something to further research - maybe just how those
things work... :)

--Danny

2006\04\09@184125 by Russell McMahon

face
flavicon
face
> ... I made an electric fence to keep snails out of the
> veges.

You could sell the concept to Gallagher.


       RM

2006\04\09@190349 by Jinx

face picon face

> > ... I made an electric fence to keep snails out of the
> > veges.
>
> You could sell the concept to Gallagher.

I made the first in the mid-80s, long before anything like the
Interweb was around, and don't recall it not being an original
idea. However, it's fairly easy to find similar products these
days, eg

http://www.snailaway.com/press/press_images/snailaway_assembly/index.html

2006\04\09@190724 by Bob Axtell

face picon face
Russell McMahon wrote:

>>... I made an electric fence to keep snails out of the
>>veges.
>>    
>>
>
>You could sell the concept to Gallagher.
>
>
>        RM
>
>  
>
Is Gallagher still around? Hasn't run out of melons yet?

- - -

Actually, Jinx and his gold wires look like a fix. I am driving it with
an "AC driver" through all six sections of a CD40106. A PIC16F676
will sense the inputs, smooth everything, then drive the a solenoid value.
I am also making the PIC time the fountain... I am having it come on
for 14 hrs after detecting daylight, defined as at least two hours without
light, followed by at least 15 minutes  OF light...but when you mash the
red switch you can break the cycle momentarily, making the fountain go
on at will. The "AC" swings from +5V to -5V to prevent etching the gold
wires.

After buying the parts on the web, I discovered that ALL ELECTRONICS
(a surplus house) sells battery-operated water-level detectors.... Oh will,
mine will be more complex and hopefully work better,,,

BTW, you have tossed out some good informative links lately. Do you
EVER sleep?

--Bob

--
Note: To protect our network,
attachments must be sent to
attachspamKILLspamengineer.cotse.net .
1-520-850-1673 USA/Canada
http://beam.to/azengineer

2006\04\09@193009 by Jinx

face picon face
> After buying the parts on the web, I discovered that ALL
> ELECTRONICS (a surplus house) sells battery-operated
> water-level detectors

Oh, any chump can BUY one ;-)  (not for a minute suggesting
you're a circuit-buying chump you unnerstand)

2006\04\09@212438 by William Chops Westfield

face picon face

On Apr 9, 2006, at 4:30 PM, Jinx wrote:

>> I discovered that ALL ELECTRONICS sells battery-operated
>> water-level detectors
>
> Oh, any chump can BUY one ;-)

I find that it puts a serious crimp in my enthusiasm if there
is a commercial product that comes very close to doing what I
want my project to do :-(

BillW

2006\04\09@230245 by Jinx

face picon face

> > Oh, any chump can BUY one ;-)
>
> I find that it puts a serious crimp in my enthusiasm if there
> is a commercial product that comes very close to doing what I
> want my project to do :-(

I know - it's a terrible decision to make sometimes. "Is 'very
close' close enough to stop me making one right now, or will I
one day get sick of what it can't do and make it then ?"

A couple of times though I've done it anyway and come across
a much better way than the commercial product. And subsequently
made no attempt to commercialise that way ;-(

2006\04\10@154727 by alan smith

picon face
Sprauge used to make a water level detect chip....sensors were ac driven.  Built some to monitor my overflow and washer tanks on my truck

Bob Axtell <.....engineerKILLspamspam.....cotse.net> wrote:  Russell McMahon wrote:

{Quote hidden}

Is Gallagher still around? Hasn't run out of melons yet?

- - -

Actually, Jinx and his gold wires look like a fix. I am driving it with
an "AC driver" through all six sections of a CD40106. A PIC16F676
will sense the inputs, smooth everything, then drive the a solenoid value.
I am also making the PIC time the fountain... I am having it come on
for 14 hrs after detecting daylight, defined as at least two hours without
light, followed by at least 15 minutes OF light...but when you mash the
red switch you can break the cycle momentarily, making the fountain go
on at will. The "AC" swings from +5V to -5V to prevent etching the gold
wires.

After buying the parts on the web, I discovered that ALL ELECTRONICS
(a surplus house) sells battery-operated water-level detectors.... Oh will,
mine will be more complex and hopefully work better,,,

BTW, you have tossed out some good informative links lately. Do you
EVER sleep?

--Bob

--
Note: To protect our network,
attachments must be sent to
EraseMEattachspam_OUTspamTakeThisOuTengineer.cotse.net .
1-520-850-1673 USA/Canada
http://beam.to/azengineer

2006\04\10@165425 by Peter

picon face

Water kettle method. Float with magnet inside, reed outside. Metal strip
runs outside and keeps float from wandering off.

Peter

2006\04\10@181526 by Bob Axtell

face picon face
Browsing the technical literature I found a GREAT way to measure the
presence of epid water.  It is similar to how liquids are measured
in a flow meter.

You place a resistor and a thermistor in close proximity at the end of an
insulated probe. You shroud it slightly with a plastic shield to trap
the heat
except that water can still flow into the shield easily.

When the water is NOT touching the probe, the resistor heats the
thermistor to a steady-state point, above normal ambient.

When water touches the probe, it removes heat from the probe constantly
and reduces the temperature... reflected by the R-value of the thermistor.

Even better than the gold wires, which depend on the conductivity of the
water itself, which varies according to the chlorine inserted into the
water and the water useage rate....

Comments welcome.

--Bob

--
Note: To protect our network,
attachments must be sent to
attachspamspam_OUTengineer.cotse.net .
1-520-850-1673 USA/Canada
http://beam.to/azengineer

2006\04\10@182506 by David VanHorn

picon face
I suppose a gamma switch is out?

--
Feel the power of the dark side!  Atmel AVR

2006\04\10@182703 by Richard Prosser

picon face
On 11/04/06, Bob Axtell <@spam@engineerKILLspamspamcotse.net> wrote:
{Quote hidden}

Or combine the 2 & use a PTC?
You only need to measure the voltage accross it to figure out if it's
in the water - provided you don't go overboard with the drive current.

RP

2006\04\10@190549 by Jinx

face picon face
> When the water is NOT touching the probe, the resistor heats the
> thermistor to a steady-state point, above normal ambient.

> Comments welcome.

Bob, that method sounds OK, but would definitely need more set-up
time spent on it. Unless you're after developing it for another application
that deserves the complexity, is it worth the time ?

2006\04\10@191916 by Bob Axtell

face picon face
Jinx wrote:

>>When the water is NOT touching the probe, the resistor heats the
>>thermistor to a steady-state point, above normal ambient.
>>    
>>
>
>  
>
>>Comments welcome.
>>    
>>
>
>Bob, that method sounds OK, but would definitely need more set-up
>time spent on it. Unless you're after developing it for another application
>that deserves the complexity, is it worth the time ?
>
>  
>
I am designing it both ways, I think. I am only making 4 PCBs, two
fountains and a spare
PCB for both of 'em (my neighbor wants one too).

--Bob

--
Note: To protect our network,
attachments must be sent to
RemoveMEattachTakeThisOuTspamengineer.cotse.net .
1-520-850-1673 USA/Canada
http://beam.to/azengineer

2006\04\11@055003 by Tony Smith

picon face
> The problem is that in So Arizona, the water evaporates so fast, I
> can't discipline myself to keep it filled. So... I am gonna design a
> slick way to sense when the water level is low so it can kick on a
> solenoid and pump some back into it. I don't want to use anything
> ugly, or big (like a float valve). I had in mind a  non-contact sensor,
> perhaps a capacitor. The whole sensor/solenoid deal could then
> be automatic.


Make a capacitor.  Take a plastic tube, and run 2 strips of adhesive foil
down opposite sides.  You could use that stuff you put on windows for
alarms, or copper foil that stained glass people use.

I used the copper foil (because I had some), added wires to one end, then
water-proofed it by putting some heatshrink over it (but I put some
sealant on the ends first).

The capacitance changes as the water level goes up & down.  Works well.
Won't corrode like bare wires either.  Use clear tubing & heatshrink and
it might not stand out all that much either.

Of course, you'll need a PIC to measure the capacitance... and fire the
solenoid...

I got this from the Parallex website (Basic Stamp), there's an article
about it on there somewhere.

Tony

2006\04\11@071759 by Russell McMahon

face
flavicon
face
>> You place a resistor and a thermistor in close proximity at the end
>> of an
>> insulated probe. You shroud it slightly with a plastic shield to
>> trap
>> the heat
>> except that water can still flow into the shield easily.
>>
>> When the water is NOT touching the probe, the resistor heats the
>> thermistor to a steady-state point, above normal ambient.

With some thought this could serve to both measure water temperature
AND to detect absence of water.

Heat resistor (or PTC) enough to raise its temperature in air to say
80 C +.

When water is present sensor temperature will drop to a known
temperature above water's temperature. The better the heat transfer
provisions the better they match.

Air cooling rate will also vary as water cooling ability is varied.
Calibration probably required.

A Peltier device may be useful here.

A pulsed sensor where delta temperature rise with time is sensed would
allow liquid temperature measurement AND detection of liquid absence
without having to operate the sensor at a high temperature in air.


       RM

2006\04\11@091629 by Bob Axtell

face picon face
Tony Smith wrote:

{Quote hidden}

would it operate 25' from the fountain? I was trying to avoid having the
electronics close
to the fountain, or splitting it up...my planned electronics box is near
the water spigot &
outside electrical outlet...

I already have copper shielding foil and a support to hold it...Do you
think I could use that
low-loss TV interconnect cable for a 25' run? That could be buried
alongside the power
cable to the pump motor.

Good tip, thanks.

--
Note: To protect our network,
attachments must be sent to
spamBeGoneattachspamBeGonespamengineer.cotse.net .
1-520-850-1673 USA/Canada
http://beam.to/azengineer

2006\04\11@092434 by Bob Axtell

face picon face
But, ya know, if I mounted a PIC10 right at the top of the probe itself, I
could simply send a 5V "level" signal, can easily go 25', and no cable
capacitance issues.

My wife has some leftover 2-part clear epoxy that seals HARD. No
moisture problems with that.

I'm intrigued. Gonna look at Parallex site.

--Bob

{Quote hidden}

--
Note: To protect our network,
attachments must be sent to
TakeThisOuTattachEraseMEspamspam_OUTengineer.cotse.net .
1-520-850-1673 USA/Canada
http://beam.to/azengineer

2006\04\11@114129 by Peter

picon face


On Sun, 9 Apr 2006, William Chops Westfield wrote:

> I find that it puts a serious crimp in my enthusiasm if there
> is a commercial product that comes very close to doing what I
> want my project to do :-(

And one of the best known ways to stifle certain developments of the
competition is to pre-announce a device that does just what they are
developing (or counteracts it). Don't fall for it, do your calcs and if
it looks good do it. After all, if they are selling it and di not go
bust, then it means there is a market for it.

Peter

2006\04\12@054316 by Tony Smith

picon face
I found the article on the Parallex website:
<http://www.parallax.com/dl/docs/cols/nv/vol1/col/nv27.pdf>

I still think it's a neat solution, cheap too.

I did something similar a few years back, measuring the water in a tank.
I connected a tube to where a tap went at the bottom, and joined it the
the 'capacitor guage' stuck on the outside.  A PIC drove a 7 seg led,
showing 0 (empty) to 9 (full).  I can't remember exactly how I measured
the capacitance though... like PC joysticks, I guess.  Charge then bleed
through a resistor, time how long it takes.

It was close to the house so running power to it wasn't a problem.  It
occurs to me now that if I'd used clear tubing, you could see the water
level too.   Drop in a bright red bead to act as a float, like a kettle,
but where's the fun in that.

It also occured to me that it may not work if you stuck it in the middle
of a pond, as opposed to the side of a tank, but I can't see why not.  The
capacitance depends on the amount air between the plates, having water on
both sides won't make a difference.

If you put a PIC on top, you might as well send back the exact water level!

Tony



{Original Message removed}

2006\04\12@070407 by Alan B. Pearce

face picon face
>I found the article on the Parallex website:
><http://www.parallax.com/dl/docs/cols/nv/vol1/col/nv27.pdf>
>
>I still think it's a neat solution, cheap too.

I was envisaging a tube that went down into the water. have to think how I
can apply this to a water butt.

>If you put a PIC on top, you might as well send back
>the exact water level!

True, but also measure the temperature and turn on some mild warmth if it
looks like freezing, so the water butt doesn't get damaged, in my case.

2006\04\13@044914 by Tony Smith

picon face
The tube can be open ended, no need to seal it.  I thought it might not
work, but can't think of a reason.  The capacitance would read the same.
For the tank, I put the tube on the outside because it was easier, and
well, it never really occured to me to put it inside.

Hmmm, motorcycle fuel gauge...

I was originally going to put a small magnet on a float inside the tube,
and have a few reed switches outside.  That would work for a pond level
indicator (reed switches are easier to deal with than hall effects), but
you need to figure out how to stop the magnet spinning.

Tony



{Original Message removed}

2006\04\13@090055 by Howard Winter

face
flavicon
picon face
Tony,

On Thu, 13 Apr 2006 18:49:06 +1000 (EST), Tony Smith wrote:

>...
> I was originally going to put a small magnet on a float inside the tube,
> and have a few reed switches outside.  That would work for a pond level
> indicator (reed switches are easier to deal with than hall effects), but
> you need to figure out how to stop the magnet spinning.

Mount it vertically, then it won't matter if it spins...

Cheers,


Howard Winter
St.Albans, England


2006\04\13@102833 by Bob Axtell

face picon face
Tony Smith wrote:

>The tube can be open ended, no need to seal it.  I thought it might not
>work, but can't think of a reason.  The capacitance would read the same.
>For the tank, I put the tube on the outside because it was easier, and
>well, it never really occured to me to put it inside.
>
>  
>
I am allowing the water to enter the round tube, because this increases
the surface area
and makes it more sensitive...

>Hmmm, motorcycle fuel gauge...
>
>I was originally going to put a small magnet on a float inside the tube,
>and have a few reed switches outside.  That would work for a pond level
>indicator (reed switches are easier to deal with than hall effects), but
>you need to figure out how to stop the magnet spinning.
>  
>
That's a problem, because the fuel sloshes around too much.

--Bob

>Tony
>
>
>
>{Original Message removed}

2006\04\13@144025 by Peter

picon face


On Thu, 13 Apr 2006, Tony Smith wrote:

{Quote hidden}

If you put a magnet float in the water and a metal wire outside the
magnet will be drawn near the metal wire. Add two reed switches near the
wire and it's done. The magnet float need to be attached to anything, it
can be a plastic flower or orb or whatnot.

Peter

2006\04\14@235615 by Tony Smith

picon face
>...
> I was originally going to put a small magnet on a float inside the tube,
> and have a few reed switches outside.  That would work for a pond level
> indicator (reed switches are easier to deal with than hall effects), but
> you need to figure out how to stop the magnet spinning.

Mount it vertically, then it won't matter if it spins...

Cheers,

Howard Winter
St.Albans, England


But then you can only have one sensor...  well two, maybe.  For the pond
you need two sensors, (high & low level) else you get chatter.

And I noticed my local electronic shop (Jaycar in Oz) has heatshrink with
glue inside it, just what you need for a waterproof setup like this.  Only
in black though.

Tony

2006\04\15@002526 by Tony Smith

picon face
>Hmmm, motorcycle fuel gauge...
>
>I was originally going to put a small magnet on a float inside the tube,
>and have a few reed switches outside.  That would work for a pond level
>indicator (reed switches are easier to deal with than hall effects), but
>you need to figure out how to stop the magnet spinning.
>

That's a problem, because the fuel sloshes around too much.

--Bob


Sloshing fuel can be overcome with averaging, I guess.  It doesn't move
about much overall anyway.  Just ignore reading during braking &
acceleration, where you're not really interested in the fuel level anyway.

Can't be worse than the average motorcycle fuel gauge, which has 3 levels,
full, not quite empty, and empty.  These exist only in your mind, of
course.  The holy grail isn't the cup Jesus drank from, it's the accurate,
working  fuel gauge on the bike he rode.

Standard procedure is to ride the bike until it stops.  At this point
either the main tank is empty, so you switch to the reserve, or you'd
forgotten to switch it back last time you refuelled, so you get to push
and swear at it.

Once on the reserve, you now have usually 3 litres on fuel, and (in my
case) that's 50-100km depending on the bike, enthusiam, and hills that you
can coast down with the engine off.

Some Harleys have fuel guages (floats, I think), but they often have 2
separate tanks, so the guage only measures one, and yes, you do have to
fill both of them.  Some have a light that comes on at reserve, but you'd
already figured that when the bike stopped.  Unless it doesn't have a
reserve, and the indicator bulb is blown...

Did Ford have a capacitive fuel guage at one point?  So do some
helicopters, don't they?

Tony

2006\04\15@071507 by Vasile Surducan

face picon face
On 4/9/06, Bob Axtell <RemoveMEengineerspamTakeThisOuTcotse.net> wrote:
{Quote hidden}

A fountain automation it can't be without a PIC. Telemetry, ultrasonic
range finder, laser beams...using top DSP or ARM cores...
:)
Maybe a simple mercury sealed switch (floating on the water surface)
connected directly (or using a relay) into your low power pump circuit
? No PIC, allowing a long distance to pump and safe histeresys. The
smallest I've seen looks like a watch bulb.

greetings,
Vasile



Lotsa talent here. I have piles of PICs, can always
{Quote hidden}

> -

2006\04\15@083117 by Howard Winter

face
flavicon
picon face
Tony,

On Sat, 15 Apr 2006 13:56:08 +1000 (EST), Tony Smith wrote:

> I previously said:

>> Mount it vertically, then it won't matter if it spins...
>
> But then you can only have one sensor...  well two, maybe.  For the pond
> you need two sensors, (high & low level) else you get chatter.

No, you'll find that reed switches have quite a sharp operating point when you're moving the magnet along the
axis at a constant radial distance - much sharper than if you're moving it radially.  And there's quite high
hysteresis in both cases, so I don't think you'd get chatter unless the water level is waving up and down half
an inch or so.  Try a "dry" test on a piece of paper and plot the operating/release points, and I think you'll
see what I mean.

> And I noticed my local electronic shop (Jaycar in Oz) has heatshrink with
> glue inside it, just what you need for a waterproof setup like this.  Only
> in black though.

I've only seen it in black (and it's darned expensive!).  You could put glue of your own at both ends of
ordinary heat-shrink, but I'm not sure what type would stick to it.

Incidentally, I don't know how big your fountain is, or what size of sensor you're looking for, but these:
http://www.rapidelectronics.co.uk/rkmain.asp?PAGEID=80010&CTL_CAT_CODE=&STK_PROD_CODE=M36677&XPAGENO=1  are
pretty small, and cheap!  Only problem I can see is if the length of the mounting stem isn't long enough for
your water depth.

Cheers,


Howard Winter
St.Albans, England


More... (looser matching)
- Last day of these posts
- In 2006 , 2007 only
- Today
- New search...