Sorta OT: Underwater Sensing
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Posts: 46,084
As this list has some of the most intelligent people I know of on it...
I need a method (using a Stamp, of course) to detect a metal object
underwater.
Here is a brief description of the application:
1. Part comes down the roller conveyor and stops above a water tank.
2. Operator presses start button.
3. Two motors start and lower a lengthy section of the conveyor (and the
part) into a tank of water.
4. When the conveyor reaches bottom of tank, I must somehow sense this
so I know when to turn the motors off.
5. Process continues...
I do not wish to decrease the integrity of the tank in any way (no
drilling of holes)!
Solution doesn't have to be cheap -- its going into a commercial
application and must be reliable!
Thanks,
Arron
I need a method (using a Stamp, of course) to detect a metal object
underwater.
Here is a brief description of the application:
1. Part comes down the roller conveyor and stops above a water tank.
2. Operator presses start button.
3. Two motors start and lower a lengthy section of the conveyor (and the
part) into a tank of water.
4. When the conveyor reaches bottom of tank, I must somehow sense this
so I know when to turn the motors off.
5. Process continues...
I do not wish to decrease the integrity of the tank in any way (no
drilling of holes)!
Solution doesn't have to be cheap -- its going into a commercial
application and must be reliable!
Thanks,
Arron
Comments
hangs on. When it gets to the bottom of the tank, the load on the supporting
piece should decrease.
Original Message
> As this list has some of the most intelligent people I know of on it...
>
> I need a method (using a Stamp, of course) to detect a metal object
> underwater.
>
> Here is a brief description of the application:
> 1. Part comes down the roller conveyor and stops above a water tank.
> 2. Operator presses start button.
> 3. Two motors start and lower a lengthy section of the conveyor (and the
> part) into a tank of water.
> 4. When the conveyor reaches bottom of tank, I must somehow sense this
> so I know when to turn the motors off.
> 5. Process continues...
>
> I do not wish to decrease the integrity of the tank in any way (no
> drilling of holes)!
>
> Solution doesn't have to be cheap -- its going into a commercial
> application and must be reliable!
>As this list has some of the most intelligent people I know of on it...
>
>I need a method (using a Stamp, of course) to detect a metal object
>underwater.
>
>Here is a brief description of the application:
>1. Part comes down the roller conveyor and stops above a water tank.
>2. Operator presses start button.
>3. Two motors start and lower a lengthy section of the conveyor (and the
>part) into a tank of water.
>4. When the conveyor reaches bottom of tank, I must somehow sense this
>so I know when to turn the motors off.
>5. Process continues...
>
>I do not wish to decrease the integrity of the tank in any way (no
>drilling of holes)!
>
>Solution doesn't have to be cheap -- its going into a commercial
>application and must be reliable!
I'd use a suitably located proximity sensor on the supports that lower the
conveyor - preferably located up out of the water. If the conveyor is
supported and lowered from the bottom, then use a waterproof prox
sensor. The prox sensor will give a simple on/off (open/closed) indication
- no Stamp required unless you need to confirm other things at the same
time before going to the next operation... or whatever.
73 de Jim, KB3PU
conveyor (so that it activates when touching its bottom) would work.
Also a reedswitch activated by a magnet fixed on the lowest part of the
conveyor (or the other way round, a magent at the bottom and the reed on
the conveyor) could do the job, provided the conveyor always land at the
same place!.
You could use many more complicated solutions, such as load cells, starin
gauges, photoelectric detectors, proximity switches of many kinds
(inductive, capacitive), depth pressure detectors, even sonar type devices.
But why bother if there seem to be simple, obvious solutions?.
However, if you are asking for help, it might be that you have another
problem which has not been clear for those in the list trying to help.
Why do you say "I have to detect an object under water" if you already have
it attached to the "lengthy part" of your conveyor?
Please ellaborate....
regards,
Jose Luis
At 19:28 04/10/2001 -0500, you wrote:
>I would put a strain gauge or load cell on whatever the conveyor section
>hangs on. When it gets to the bottom of the tank, the load on the supporting
>piece should decrease.
>
>
Original Message
>
> > As this list has some of the most intelligent people I know of on it...
> >
> > I need a method (using a Stamp, of course) to detect a metal object
> > underwater.
> >
> > Here is a brief description of the application:
> > 1. Part comes down the roller conveyor and stops above a water tank.
> > 2. Operator presses start button.
> > 3. Two motors start and lower a lengthy section of the conveyor (and the
> > part) into a tank of water.
> > 4. When the conveyor reaches bottom of tank, I must somehow sense this
> > so I know when to turn the motors off.
> > 5. Process continues...
> >
> > I do not wish to decrease the integrity of the tank in any way (no
> > drilling of holes)!
> >
> > Solution doesn't have to be cheap -- its going into a commercial
> > application and must be reliable!
>
>
>
>
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>Body of the message will be ignored.
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>
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[noparse][[/noparse]Non-text portions of this message have been removed]
sealed, quite inexpensive, and operate reliably for a great number of cycles
if the current through the contacts is kept low. You could affix multiple
magnets along the conveyor with multiple reed switches in a fixed position
to generate a binary code to indicate the absolute position of the conveyor,
if desired; this could be used to control the "ballistics" of the conveyor
(i.e.: slowly increasing the velocity while ascending/descending, and
decelerating smoothly near the end of travel, saving time)
Hope this helps...
Steve
before it reaches the bottom of the tank. The sensor is never triggered, so
the lowering device keeps on running.
Original Message
> A simple (though waterproof), mechanical switch fixed to the bottom of the
> conveyor (so that it activates when touching its bottom) would work.
>
> Also a reedswitch activated by a magnet fixed on the lowest part of the
> conveyor (or the other way round, a magent at the bottom and the reed on
> the conveyor) could do the job, provided the conveyor always land at the
> same place!.
>
> You could use many more complicated solutions, such as load cells, starin
> gauges, photoelectric detectors, proximity switches of many kinds
> (inductive, capacitive), depth pressure detectors, even sonar type
devices.
> But why bother if there seem to be simple, obvious solutions?.
>
> However, if you are asking for help, it might be that you have another
> problem which has not been clear for those in the list trying to help.
>
> Why do you say "I have to detect an object under water" if you already
have
> it attached to the "lengthy part" of your conveyor?
the water. You know the distance between the conveyor and the bottom of the
tank so some stops or switch actuators on the cable would work. How about
sensing the rotations of the motor using hall effect sensor. You could use a
automotive spedo sensor which will sense gear teeth also some hall effect
sensors do this
Original Message
From: <agarb@j...>
To: <basicstamps@yahoogroups.com>
Sent: October 04, 2001 4:59 PM
Subject: [noparse][[/noparse]basicstamps] Sorta OT: Underwater Sensing
| As this list has some of the most intelligent people I know of on it...
|
| I need a method (using a Stamp, of course) to detect a metal object
| underwater.
|
| Here is a brief description of the application:
| 1. Part comes down the roller conveyor and stops above a water tank.
| 2. Operator presses start button.
| 3. Two motors start and lower a lengthy section of the conveyor (and the
| part) into a tank of water.
| 4. When the conveyor reaches bottom of tank, I must somehow sense this
| so I know when to turn the motors off.
| 5. Process continues...
|
| I do not wish to decrease the integrity of the tank in any way (no
| drilling of holes)!
|
| Solution doesn't have to be cheap -- its going into a commercial
| application and must be reliable!
|
| Thanks,
| Arron
|
| 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/
|
|
Original Message
> From: Chris Loiacono [noparse]/noparse]mailto:[url=http://forums.parallaxinc.com/group/basicstamps/post?postID=lTVTPc0OPXIQKlMnrmadoMullQQJAEpt6TC8QrDuS6EO8YSSXr4h183PqCZe6HYGnG9LL87TXX1E]chris@m...[/url
> Sent: Friday, October 05, 2001 11:26 AM
> To: 'basicstamps@yahoogroups.com'
> Subject: RE: [noparse][[/noparse]basicstamps] Sorta OT: Underwater Sensing
>
>
> If you don't want to submerge wiring in the tank, you may
> consider a low-voltage sensor that will switch when a pair of
> electrodes reaches the water level from above. Perhaps a rain
> sensor for sprinkler-systems can be had from a Plumber's
> supply, or Home Depot/Lowe's. Of course, this will not work
> well if the water is exceptionally contaminant-free.
>
> My antennae always rise when I see safety issues posted. I am
> certain there is a recognized safety standard that defines
> acceptable means of controlling this type of process with
> minimal risk. Always buy the standard(s), read them, or pay
> someone to advise on this subject. The effort is always well
> worth the reduction in legal fees and fines.
>
> Chris
>
> >
Original Message
> > From: agarb@j... [noparse]/noparse]mailto:[url=http://forums.parallaxinc.com/group/basicstamps/post?postID=9iNAGQ4HRs6_0jMzqQCu7CBT80BuzQ4c5PB4rkehrcU0EY716YG58L1VgBDQIzJnJ4nqiVr8OA]agarb@j...[/url
> > Sent: Thursday, October 04, 2001 8:00 PM
> > To: basicstamps@yahoogroups.com
> > Subject: [noparse][[/noparse]basicstamps] Sorta OT: Underwater Sensing
> >
> >
> > As this list has some of the most intelligent people I know
> > of on it...
> >
> > I need a method (using a Stamp, of course) to detect a metal object
> > underwater.
> >
> > Here is a brief description of the application:
> > 1. Part comes down the roller conveyor and stops above a
> water tank.
> > 2. Operator presses start button.
> > 3. Two motors start and lower a lengthy section of the
> > conveyor (and the
> > part) into a tank of water.
> > 4. When the conveyor reaches bottom of tank, I must somehow
> > sense this
> > so I know when to turn the motors off.
> > 5. Process continues...
> >
> > I do not wish to decrease the integrity of the tank in any way (no
> > drilling of holes)!
> >
> > Solution doesn't have to be cheap -- its going into a commercial
> > application and must be reliable!
> >
> > Thanks,
> > Arron
> >
> > 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/
> >
> >
>