Capacititative sensing of liquid level

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It seems to me that the bubbler method would be the best route to go. I believe you would have a calibration problem with the capacitative sensor with different beer styles.
 
kenh said:
It seems to me that the bubbler method would be the best route to go. I believe you would have a calibration problem with the capacitative sensor with different beer styles.
Click to expand...

It's possible. Air/steam/CO2 bubbles would be an issue same as for pressure sensors so a bubbler may also be required.

There is good reason to believe that capacitative sensors drift less than pressure sensors so they might not need zeroing every time. I might try to fix one up on my HLT just for fun.
 
Hi everybody... My first post. Thought I'd try to contribute right off the bat. I'm using a Turck BC 3-M12-AP6X-0.2M-RS 4T Capacitive level sensor on my mash tun's level tube. I machined a UHMW block that can be slid along the tube to achieve a fully covered grain bed depending on the grain bill. The sensor runs on 24v dc and powers a solid state relay for my gas fired RIMS system's #1 March 815 pump. This is the latest addition to my flat rack system and it works great! It's nice to not have to jockey flows from two pumps during fly sparging. Now I just set my desired water level over the grain bed, put the #1 pump in Auto and set my desired #2 pump flow to the boil kettle. :mug:

https://drive.google.com/file/d/0B4QaOPjh5yXqcGxQaUg5dXVZMzg/edit?usp=sharing

This is the false bottom I built for the mash tun. Went round and round with the perforated (round holes) stainless bottoms. Too many stuck sparges. Thick oatmeal porridge is nothing for this RIMS tun. :rockin:

https://drive.google.com/file/d/0B4QaOPjh5yXqeDJSczY5cU95dnM/edit?usp=sharing
 
So if I understand you, the level sensor gives an on/off signal and you slide it up and down the sight tube to set the desired level?

Interesting slotted design for the false bottom, did you get that specially machined?
 
alien said:
So if I understand you, the level sensor gives an on/off signal and you slide it up and down the sight tube to set the desired level?
Click to expand...

Correct, it can be slid up and down to set the desired level in the tun. The pump turns on only when the level gets below the view of the sensor. Sensor is tune-able for sensitivity. We've only run it in a few batches so far but it is working awesome.

Interesting slotted design for the false bottom, did you get that specially machined?
Click to expand...

No, it is one of homebrewing.org 's false bottoms that I modified for my 8 gal tun. Without question the best false bottom design IMO. In my previous system (gravity with a round cooler tun) I used one of the same style false bottoms.... but not until after struggling with stuck sparges using a couple different round hole design bottoms. Breweries don't use round hole designs in their lauter tuns... neither should we. :(
 
mxrob said:
Correct, it can be slid up and down to set the desired level in the tun. The pump turns on only when the level gets below the view of the sensor. Sensor is tune-able for sensitivity. We've only run it in a few batches so far but it is working awesome.

(
Click to expand...

Interesting, is there an affordable source?
Picked up one of these, but haven't been able to goof with it yet:
http://www.mouser.com/ProductDetail/Omron-Industrial/E2K-L26MC1/?qs=TwPrcXezm73yZ6LcOrsVFg==

Now that the mountain place is buttoned up for the winter, finishing build is on front burner again. Have stand, hardware, plumbing and electrical handled.
Haven't decided on controller yet, Brewtroller or BCS.
What are you using for the brains?
 
MrNatural said:
Interesting, is there an affordable source?
Click to expand...

They certainly do not give them away do they? :(

Picked up one of these, but haven't been able to goof with it yet:
http://www.mouser.com/ProductDetail/Omron-Industrial/E2K-L26MC1/?qs=TwPrcXezm73yZ6LcOrsVFg==
Click to expand...

Interseting... I had not checked with Omron for a sensor. Interested to see how your testing works out.

Now that the mountain place is buttoned up for the winter, finishing build is on front burner again. Have stand, hardware, plumbing and electrical handled.
Haven't decided on controller yet, Brewtroller or BCS.
What are you using for the brains?
Click to expand...

No CPU... just PID controllers and the auto mash level control. We are working on a Arduino control project with cell phone integration/control next.
 
You can DIY capacitative sensing with cheap microcontrollers, plenty of them have built in methods e.g TI MSP430 range. No need to spend big $.
 
So, what's available for us non-programmer types? I'd love to have something I can stick down in my pot to tell me the level inside. It would be real nice for my hot liquor tank since the lip of the pot is right at eye level. Right now I'm using a step stool to watch the level as I fill the pot.
 
kenh said:
Hmm, if I had a sight tube I wouldn't need a sensor.
Click to expand...

It would certainly be more cost effective to install a sight tube in your HLT. There is no reason I can think of to automate the level of the HLT anyway. The mash tun is a different story (if you are fly sparging) but I would still want visual confirmation of level for either tun. You can install a T in your outlet port for a sight tube but the accuracy is somewhat suspect when you are draining water from the valve. It is more of an issue on the mash tun however. You want a separate port for the sight tube in that case.
 
mxrob said:
It would certainly be more cost effective to install a sight tube in your HLT. There is no reason I can think of to automate the level of the HLT anyway. The mash tun is a different story (if you are fly sparging) but I would still want visual confirmation of level for either tun. You can install a T in your outlet port for a sight tube but the accuracy is somewhat suspect when you are draining water from the valve. It is more of an issue on the mash tun however. You want a separate port for the sight tube in that case.
Click to expand...

Dies anyone sell one that I can install by unscrewing my faucet, screwing in the sight tube, the re-attaching my faucet? My faucet is 1/2" threads.
 
kenh said:
Dies anyone sell one that I can install by unscrewing my faucet, screwing in the sight tube, the re-attaching my faucet? My faucet is 1/2" threads.
Click to expand...

You would just use a 1/2" T in that case. Remove the valve, install the T, install the valve on the T on the straight through thread then use a 1/2" to 3/8 OD tube compression fitting for the poly-carbonate sight tube. Remove the metal compression ferrel(s) from the compression fitting and replace with a viton or silicone o-ring of the appropriate size. You would want some sort of support for the top of the sight tube. A 1/4" stainless eye bolt is the norm.
 
But be aware that when the valve is open you won't get the right reading from the sight tube.
 
alien said:
But be aware that when the valve is open you won't get the right reading from the sight tube.
Click to expand...

Correct... this is not a good way to go for the mash tun especially. For the HLT it will work fine but if you open the valve fully (a large outflow) the level in the sight tube will show lower than it actually is within the tun. For just filling the tun it will be fine.
 
joshwoodward said:
Ultrasonic sensing can apparently have problems with hot liquids - the steam coming off of it can throw off the sensor.
Click to expand...

I understand but I want to tell how full my hot liquor tank is. It's on the top tier of my three tier brew stand and right now I have to stand on a foot stool while filling to see how much water I'm putting in that tank. And there is no steam when I'm filling.
 
kenh said:
I understand but I want to tell how full my hot liquor tank is. It's on the top tier of my three tier brew stand and right now I have to stand on a foot stool while filling to see how much water I'm putting in that tank. And there is no steam when I'm filling.
Click to expand...

I figured out the best solution to my problem. I mounted a mirror at an angle above my hot liquor tank and I just watch the mirror when I'm filling so I don't over fill.

Sometimes a low-tech solution is the best solution!!!!
 
kenh said:
I figured out the best solution to my problem. I mounted a mirror at an angle above my hot liquor tank and I just watch the mirror when I'm filling so I don't over fill.

Sometimes a low-tech solution is the best solution!!!!
Click to expand...

Yeah but it's not as fun.... :cross: Glad you git the HLT filling dilemma handled. :)
 
There are a couple of ways to do it based on your requirements. Do you want to maintain a certain level with a pump, or just know the water level? Are discrete intervals OK (1/4, 1/2, 3/4, full, etc)?

Either of the above can be done with bare wire pairs as sensors that operate colored LED's or a pump utilizing an Arduino or a Quad 2-input NOR CMOS as the logic switch. I do this to maintain the level in my grant.
 
Photo-optic ain't too shabby.

Punch a hole and mount one of these at HLT fill level. Still about 4x the cost of sightglass - 100x the cost of a mirror............

http://sensing.honeywell.com/index.php?ci_id=50127

helibrewer said:
There are a couple of ways to do it based on your requirements. Do you want to maintain a certain level with a pump, or just know the water level? Are discrete intervals OK (1/4, 1/2, 3/4, full, etc)?

Either of the above can be done with bare wire pairs as sensors that operate colored LED's or a pump utilizing an Arduino or a Quad 2-input NOR CMOS as the logic switch. I do this to maintain the level in my grant.
Click to expand...

What range of resistance/conductivity do you see per level increment?
 
I'm not measuring resistance, I'm only checking for fluid covering the bare wire ends. So for 4 levels; low, 1/4, 1/2, 3/4, and full, there would be 4 wire pairs (sensors). These sensors can provide input for any action via the Arduino, i.e. pump, LED, alarm.

For my grant I use 2 sensor pairs; one for low and one for high. My pump empties the grant when the high sensor is covered and continues to run until the low sensor is uncovered, then the grant refills.


Sent from my iPad using Home Brew
 
helibrewer said:
I'm not measuring resistance, I'm only checking for fluid covering the bare wire ends. So for 4 levels; low, 1/4, 1/2, 3/4, and full, there would be 4 wire pairs (sensors). These sensors can provide input for any action via the Arduino, i.e. pump, LED, alarm.

For my grant I use 2 sensor pairs; one for low and one for high. My pump empties the grant when the high sensor is covered and continues to run until the low sensor is uncovered, then the grant refills.


Sent from my iPad using Home Brew
Click to expand...

Correct me if I am wrong but; You would not need pairs as in two wires per level setpoint, only one wire per setpoint and a common - that is how I have seen it done in industrial probe level switches. Don't know if you could 100%, but the common could also be the pot itself if it is conductive.
 
helibrewer said:
I'm not measuring resistance, I'm only checking for fluid covering the bare wire ends. So for 4 levels; low, 1/4, 1/2, 3/4, and full, there would be 4 wire pairs (sensors). These sensors can provide input for any action via the Arduino, i.e. pump, LED, alarm.

For my grant I use 2 sensor pairs; one for low and one for high. My pump empties the grant when the high sensor is covered and continues to run until the low sensor is uncovered, then the grant refills.
Click to expand...
Dammit! That's what I love/hate about this hobby. Haven't finished LPG plumbing on my stand, or mounted one component in control box.
Instead, I've just been out at workbench eyeballing 1/2" teflon rod, two 10AWG solid copper "electrodes", silicone and 1/2" compression fittings. One at autofill and one at element safe-fire level would be great start.
mattd2 said:
Correct me if I am wrong but; You would not need pairs as in two wires per level setpoint, only one wire per setpoint and a common - that is how I have seen it done in industrial probe level switches. Don't know if you could 100%, but the common could also be the pot itself if it is conductive.
Click to expand...
That would simplify things and probably let you use 1/4" compression fittings for a single electrode.
 
Yes, one common would work fine as long as it is either always covered with fluid or connected to a conducting vessel. I use 22 gauge wire, same stuff I use for my one-wire sensors. It's three conductor aircraft wire in polypropylene insulation.


Sent from my iPad using Home Brew
 
helibrewer said:
Yes, one common would work fine as long as it is either always covered with fluid or connected to a conducting vessel. I use 22 gauge wire, same stuff I use for my one-wire sensors. It's three conductor aircraft wire in polypropylene insulation.


Sent from my iPad using Home Brew
Click to expand...


Can you post some pics of your setup? I just keep envisioning wires with the insulation stripped at the end sitting in sticky wort. Also I am assuming your common would have a current limited voltage of 5v or 3.3v and your level sensors have a pull down to gnd such that when the sensor wire is submerged it reads your high voltage otherwise it's pulled to gnd.
 
crane said:
Can you post some pics of your setup? I just keep envisioning wires with the insulation stripped at the end sitting in sticky wort. Also I am assuming your common would have a current limited voltage of 5v or 3.3v and your level sensors have a pull down to gnd such that when the sensor wire is submerged it reads your high voltage otherwise it's pulled to gnd.
Click to expand...

Here's my box, I chose to build it stand alone:

levelsensor-62045.jpg


It uses a weak pull-up resistor on each sensor, so "normally open" is logic HIGH.
 

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