Fluid Level Detection
MikeL
Posts: 6
I have plastic water/waste tanks that are inaccessable from the top to put senders in and can just barely access from one side, has anyone got suggestions for a capatacitance type sensor that can be stuck on the exterior side and monitored by a BS2. The tank wall is 3/8" thick and about 20 inches high.
I can buy ready made capacitance ones as described but the cost is a bit high, I already am monitoring other things with the BS2 so it would be great to integrate the level sensing. I've tried making a version using copper tape but am not good with the circuitry to interface something useable.
Thanks!
I can buy ready made capacitance ones as described but the cost is a bit high, I already am monitoring other things with the BS2 so it would be great to integrate the level sensing. I've tried making a version using copper tape but am not good with the circuitry to interface something useable.
Thanks!
Comments
Mount a liquid pressure transducer to pipe at or below bottom of tank..
The level in the tank will reflect on the transducer....
You can also use a float/magnet combo with hall effect or reed switches.
The best way depends on how accurate you want the readings to be, and how much $$$ you want to spend...
Bob
It can't be a rocket science (just for me), but it looks to me like a very sensitive capacitor meter.
Thanks,
Mike
as to exactly where i read it ... shrugs
good luck
Sawmiller, I saw and bullt that unit but couldn't get any readings from it. I still have it sitting on my workbench and can't find the original construction article now. Seems that excitation of that field is really critical. The principal is is there, it's just the electronics to work it right.
LSB, the QT1081 8-KEY QTouch™ SENSOR IC looks like potential but reading the manuals it has countermeasures for false alarms with water bridges, which is excatly the opposite of what I need.
Robert, what kind of pressure sensor did you have in mine, and what kind of cost? If were talking $25 a sender then it's good as long as I don't need a lot of supporting electronics to work it.
Here are a couple links to commercial units that I would like to mimic but using the Stamp II and pc interface:
Raritan has the method that is most practical for me:
http://www.raritaneng.com/pdf_files/tank_monitor/L1036s.pdf
Fireboy is doable with a lot of access problems:
http://www.fireboy-xintex.com/liquid-level-monitors.htm
Post Edited (MikeL) : 1/21/2007 6:33:54 AM GMT
Allelectronics sells this for fluid level detection:
www.allelectronics.com/cgi-bin/item/L4620/285/LIQUID_LEVEL_ALARM_IC_.html
Post Edited (originator) : 1/21/2007 6:49:17 AM GMT
If I really had to, I could drill holes into the tank sides at a steep angle and use stainless steel probes with silicon sealant, but stick-on foil tape would certainly be easier to install and no fuss or worry of leaks. And I have a roll of stick-on copper foil which needs a good use [noparse];)[/noparse]
I don't know much more about it, yet. It seems easy enough to interface... 8 bit PWM
3/8 pvc is no big deal. The caps are tiny, in the 10nF-100nF range as I recall.
I rebuilt the circuit and as best as I could adapted his BS1 code to my BS2. My readings are erratic no matter what I do, they bounce from 0 to 3600 at random, mostly from one end to the other and nothing in between.
I see there's another thread on reading a gas tank, this would be great if it worked for reading fuel too.
There are 2 companies that make external capacitative tank level guages, so I know it can be done - I'm not trying to steal there idea, just trying to integrate all my custom sensing requirements into my BS2:
New Providence Marine Systems: http://www.newprovidencemarine.com/
Snake River Electronics: www.SnakeRiverElectronics.com
Thanks
I'm going to do some capacitance test with fuel (safe environment ....outside witha safe distance) so I will be able to answer the fuel capacitance, but it will be a while, my project has not evolved enough to need the fuel level sensing yet.
James L
James L, what kind of tank is it? plastic or metal. Obviously if metal you have to do "wet" measurements, which shouldn't be a problem with capacitance, given the low sensing voltages needed I can't imagine a spark being generated. I figure if they can put an open (wet) rheostat inside the tank..... On the other hand if plastic then you're looking for the same thing I am, dry sensing.
BTW, those links I posted, I believe they sell additional sensors (3 wire, +/- & signal) for their guages for like $60 US, probably has less than $10 invested in parts.
Mike
Post Edited (MikeL) : 1/26/2007 2:04:19 AM GMT
One of the tanks I'm sensing from is an aluminum tank, the other a fibergl(expletive) tank. I want to use the same system for both.
I think I can build a capacitance probe for that.....actually much cheaper. I worked on military helicopters that used capacitance probes, so I know how they are built.
I'm going to try and see if I can get a large explosion. I doubt I will have any luck. Gasoline actually take quite a bit to ignite, usually a very hot spark with it under a fair amount of pressure.
But better to test than have a tank down the road exploding.
James L
LOL....I tried three times to edit my post....didn't realize the forum edited post for bad words......so a composite tank.
[noparse][[/noparse]edit]LOL... there will be no more cl(expletive) in this forum and no one will wear gl(expletive)es. Good news is there won't be any harr(expletive)ment either!
I wonder if we can still press buttons?[noparse][[/noparse]/edit]
Post Edited (LSB) : 1/26/2007 2:11:25 PM GMT