Roasted
New Member
Found this thread when searching Google - have just broken another glass hydrometer - would be interested in digital readout or USB link for SG and Temperature
Digital Hydrometer
- Thread starter baron
- Start date
Help Support Homebrew Talk - Beer, Wine, Mead, & Cider Brewing Discussion Forum:
Gordie
Well-Known Member
I'd be very interested in a real-time SG readings of wort run off, BK collection and fermentation progress. If I could mount a thermowell lookalike into the MLT outflow, BK and fermentor to accurately sample I'd be willing to spend more than $100.
The one problem I see with the first two, is that at lauter and BK temperatures, the temp correction isn't much more than a guess. Temp error is logarithmic, from what I understand, so I'm not sure how accurate temperature compensation could be even under ideal circumstances or without a Hal 9000 or Deep Thought processing the numbers.
The one problem I see with the first two, is that at lauter and BK temperatures, the temp correction isn't much more than a guess. Temp error is logarithmic, from what I understand, so I'm not sure how accurate temperature compensation could be even under ideal circumstances or without a Hal 9000 or Deep Thought processing the numbers.
Sawdustguy
Well-Known Member
Sorry for being a little skeptical but I have been looking for one for a very long time and the least expensive one I have found is from Cole Palmer.
Low Cost Specific Gravity Meter
http://www.coleparmer.com/catalog/large_image.asp?sku=2575520&img=2575504.jpg[/url]
Their definition of low cost is $1795. I would be very surprised if someone could come up with a digital Specific Gravity Meter/Hygromerter for under $100 although I can always hope.
Low Cost Specific Gravity Meter
http://www.coleparmer.com/catalog/large_image.asp?sku=2575520&img=2575504.jpg[/url]
Their definition of low cost is $1795. I would be very surprised if someone could come up with a digital Specific Gravity Meter/Hygromerter for under $100 although I can always hope.
Grimsawyer
Well-Known Member
I think the difference between this product and that "cheap" one, Sawdustguy, is I'm sure it won't be in something much fancier than a hobby box for the first few generations. Ghetto is what makes things for homebrewers cheap. Wonder how skeptical people were about the first few who cut the tops off of kegs vs. buying reallllly spendy stock pots. Though, I'm sure if you make something inexpensive that works just as well as what the big boys make their secret will be out and they might send someone over to break your thumbs till you raise your price so they don't loose too much money all mob style! HA!!! You got my support 110% OP!!! 
Put me down for one! I keep losing or breaking both my hydrometer or the tube you test yer wort in... 
Put me down for one! I keep losing or breaking both my hydrometer or the tube you test yer wort in... 
subscribed
Sawdustguy
Well-Known Member
I think expensive part is the physical technology to make the measurement. The digital portion should be straightforward and inexpensive. I have yet to find a simple sensor for this and I have been looking for a very long time.
This is how I understand the measurement: Imagine a weight is attached to a bar at the end and a bar is fixed on a wall. When you hit the weight by a finger, the weight starts vibrating. Now you will find that the heavier the weight becomes, the slower it vibrates and vice versa. This is because the weight will vibrate on the oscillation period specific to a substance in proportion to the mass of a weight. This means that one can determine the density of a substance by measuring its oscillation period since density becomes proportional to the mass when the volume is constant (ie. a measured sample in a tube).
All I am saying is that this is not trivial measurement technology that can be implemented cheaply at this time. This could change in the future but don't hold your breath. I never said it couldn't be done though.
This is how I understand the measurement: Imagine a weight is attached to a bar at the end and a bar is fixed on a wall. When you hit the weight by a finger, the weight starts vibrating. Now you will find that the heavier the weight becomes, the slower it vibrates and vice versa. This is because the weight will vibrate on the oscillation period specific to a substance in proportion to the mass of a weight. This means that one can determine the density of a substance by measuring its oscillation period since density becomes proportional to the mass when the volume is constant (ie. a measured sample in a tube).
All I am saying is that this is not trivial measurement technology that can be implemented cheaply at this time. This could change in the future but don't hold your breath. I never said it couldn't be done though.
I always wondered if a sensitive enough pressure sensor attached to the bottom of a hydrometer could do the trick. If you know how deep the bottom of the hydrometer is in the liquid you can easily determine the SG. This one has a 1% accuracy with a 0.5psi max pressure (your wort 4 in. down is about 0.144psi). I think the divisions on my hydrometer are spaced about 1/8 in. per point so we're looking at 0.00450 psi/point.
HONEYWELL S&C|24PCEFA6D|Pressure Sensor | Newark.com
HONEYWELL S&C|24PCEFA6D|Pressure Sensor | Newark.com
itsawolf
New Member
What you are refering to is the type of effect that has been used in determining flow as well. It's known as the coriolis effect. Measuring of differences in frequency as flow inside a vibrating tube changes can also easily be used to measure differences of frequency when SG changes. This might be a good start but you still might need a bit of cash for the vibration generating source. Good thinking... Mark
P-Lay
Well-Known Member
From what I understand, refractometers aren't very accurate with alcohol present so they're not able to be used after/during fermentation. I think someone in this thread said that the readings were only altered by .001 even after fermentation. If that is the case, I found something that might work in brewing (here), but is still very pricey at ~$995, but cheaper than other alternatives I've found. It also has a 4-20 mA output to trigger a relay or something (when a setpoint is reached, I assume).
Are refractometers accurate enough to be used when alcohol is present in a fermentation monitoring type situation?
I could think of a few good uses for an in-line digital hydrometer or refractometer during fermentation. Count me in if this is still being pursued.
Are refractometers accurate enough to be used when alcohol is present in a fermentation monitoring type situation?
I could think of a few good uses for an in-line digital hydrometer or refractometer during fermentation. Count me in if this is still being pursued.
ClaudiusB
Well-Known Member
Look at the accuracy.
Accuracy: better than 5% of span
The 4-20 mA output represents the measured value you can read into an analog module, chart recorder or any other mA input control device, not used to turn on a common off the shelve relay directly.
If we use 40 Brix span for example : 4 mA = 0 Brix, 8 mA = 20 Brix, 20 mA = 40 Brix
All my temperature controllers have the 4-20 mA output.
Cheers,
ClaudiusB
rsmith179
Well-Known Member
What type of sensors would you be utiilizing for this project?
camiller
Well-Known Member
Formula for compensation of ethanol effect on refractometer: SG=1.001843-0.002318474(OB)-0.000007775(OB^2)-0.000000034(OB^3)+0.00574(AB) +0.00003344(AB^2)+0.000000086(AB^3)
SG = Specific Gravity, OB = Original Brix, AB = Actual Brix (Brix Readings During Fermentation)
Copied from here:
- ValleyVintner Main Page
My next "big" purchase is going to be a refractometer.
P-Lay
Well-Known Member
kaiser423
Well-Known Member
I've read some papers on utilizing RF frequencies to determine the ABV% and sugar amounts in wine.
Essentially, you pick two different frequencies; one that is heavily attenuated by sugars, and one that is by alcohol. You construct some waveguides that have little holes in them to let fluid fill in. You measure the loss with nothing in it or just water as a cal, and then you dunk it in the tank.
Presto! Sugar and ABV measurements!
I looked up the oscillators for the frequencies necessary, and you can get some surface mount devices for ~$30 each. Two frequencies, so $60 right there.
I think that you could machine some waveguide or something that would work on this scale for somewhat cheap (~$20?).
Then you'd need a power meter on the far end...I think that surface mount versions of those are like $20 also.
All in all you're talking about ~$150 or so if you can pull everything off relatively cheaply. But it would tell you ABV also....that might make it worthwhile :rockin:
You'd have to get a little creative with the waveguide; the lower frequency is in S-Band, so a standard waveguide would be about the diameter of a pringles can. The higher frequency is in X-Band, so the diameter would be about a third....I'm sure that with a little research, a novel solution to that problem could be found though......a coaxial waveguide structure? Gap plates? Dielectrically load a portion of the waveguide?
Two wrapped dipoles that you can paste to your carboy/bucket, calibrate and then fill with liquid (the user would have to enter the distance between the antennae). Lots of interesting ideas...I may not sleep tonight now!!!!
If you're interested, I can shoot the paper your way.
EditL Spectroscopy might be another way....I know that they make pretty cheap devices for alcohol (couple hundred bucks), but I don't know of anything that would work for sugars....I'm not sure that there's a fingerprint for sugars in the near IR region...
Essentially, you pick two different frequencies; one that is heavily attenuated by sugars, and one that is by alcohol. You construct some waveguides that have little holes in them to let fluid fill in. You measure the loss with nothing in it or just water as a cal, and then you dunk it in the tank.
Presto! Sugar and ABV measurements!
I looked up the oscillators for the frequencies necessary, and you can get some surface mount devices for ~$30 each. Two frequencies, so $60 right there.
I think that you could machine some waveguide or something that would work on this scale for somewhat cheap (~$20?).
Then you'd need a power meter on the far end...I think that surface mount versions of those are like $20 also.
All in all you're talking about ~$150 or so if you can pull everything off relatively cheaply. But it would tell you ABV also....that might make it worthwhile :rockin:
You'd have to get a little creative with the waveguide; the lower frequency is in S-Band, so a standard waveguide would be about the diameter of a pringles can. The higher frequency is in X-Band, so the diameter would be about a third....I'm sure that with a little research, a novel solution to that problem could be found though......a coaxial waveguide structure? Gap plates? Dielectrically load a portion of the waveguide?
Two wrapped dipoles that you can paste to your carboy/bucket, calibrate and then fill with liquid (the user would have to enter the distance between the antennae). Lots of interesting ideas...I may not sleep tonight now!!!!
If you're interested, I can shoot the paper your way.
EditL Spectroscopy might be another way....I know that they make pretty cheap devices for alcohol (couple hundred bucks), but I don't know of anything that would work for sugars....I'm not sure that there's a fingerprint for sugars in the near IR region...
Sawdustguy
Well-Known Member
I am an EE. I am interested in the paper. It sounds interesting and definetly feasible but the commercial market for such a device sounds limited especially at the price it would fetch. The NRE costs for a device like this are not trivial and of course would be built in to the price of the device making it fairly expensive not to mention the cost of the parts and manufacturing.
kaiser423
Well-Known Member
That definitely is the truth! I was actually thinking last night that you could possibly do a stripline(? I don't remember the exact geometry) between two PCB boards so that the runs are just traces on dielectrically controlled FR-4. When you immerse it, you'll have the fluid in the middle. As long as its designed to take into account that dielectric loading, you wouldn't need any waveguide or any transitions. You would have two pcb boards, one that would have two oscillators, the strip, two power meters and a temperature sensor. That would help keep the cost down some...
Or a coplanar waveguide or something where the fluid interacts with the field in some way. One issue with this is getting enough loss to get your accuracy up. In 1.5" I think they measured ~0.5dB of loss; If you did 6" you might have enough resolution on a fairly cheap surface mount power meter to make a good measurement.
I'll send you the paper when I get back home this evening. If you have an IEEE membership to the Antennas & Propagation Society, you could do a search for it and find the paper in their archives.
edit: some possible geometries: http://www.ycars.org/EFRA/Glossary/Stripline - Microwave Encyclopedia - Microwaves101_com.htm
http://www.pcblibraries.com/Forum/forum_posts.asp?TID=87
I will have to think about this some...maybe fire up some simulation software...
Pangea
Well-Known Member
If you want to see how it's done industrially, google "flow through density meter". Industrially they dont call them in-line hydrometers, like you'd think they would. I use one in a wastewater treatment plant to measure SG. It works very well and is also very expensive. The unit sits external, in-line with process piping, and must have flow to measure. I use a little bleed line from a main pressured process line that drains back to the vessel it came from, and the density meter is in that bleed line measuring density of the liquid flowing at about 1 gpm.
If I was a commercial brewery, I would invest the $1000 in a flow though unit like this for all sorts of applications - MashTun/Boil Kettle Pre-boil Gravity and OG would be a couple.
If I was a commercial brewery, I would invest the $1000 in a flow though unit like this for all sorts of applications - MashTun/Boil Kettle Pre-boil Gravity and OG would be a couple.
camiller
Well-Known Member
For what it is worth that Valley Vintner link also has a spreadsheet with the formula implemented
also I think I read that promash will do this for you as well.MMW
Well-Known Member
If you would, please send a copy my way. MSEE in '02 (signal processing/digital com spec), 4 yrs working research in the telecom field before I got tired of the lab and computer grind and moved out to the oilfield to break rocks
. It'd be nice to dust off a couple of the old texts.
kaiser423
Well-Known Member
PM me with how I should get you the paper that you guys wanted. I thought that I could just upload it to my site, but I guess that I didn't pay the fee for this year, so I'm without web space...
MerryMonk
Member
It would also be nice if it had the ability to monitor more than one beer at a time. So you could just hit a button and scroll through up to say 4 beers at any given time.
Sawdustguy
Well-Known Member
Just out of curiousity how much would you pay for such a device?
Sawdustguy
Well-Known Member
For the technology required for such a device, $150 just won't cut it.
mal209
Member
that might not be the case...
use an arduino development board and you could control and interface 15 digital signals for 35$ (cost of board + usb connector to computer interface).
As for the actual measuring, i had a few ideas... ive thought about this extensivly, and i guess the first unknown which my ideas are based off of would be could you assume a sight glass in your fermentor/mash tun/keggle/etc. there are two possible methods you could use. If you had a closed loop sightglass (to prevent oxidation of course) you could simply
a) place a hydrometer in that and just read it....
b) make something hydrometer shaped... maybe a testtube or the like. and place a Potentiometer on the outside of the sightglass. you put something ferrious in the testtube, and as it moved up and down, like a hydrometer, it would electronically register on the potentiometer... an analog version of reading the numbers on the hydrometer.
c) tether a float to the bottom and attach a strain gauge to the line. The strain gauge would register high resistances (when strained) for low SG and low resistances (when un-strained) for high SG. you could place this float in a bracket of some sorts, and you could make it movable instead of permanent mounting. Strain gauges are linear over most of their range, so you would only have to make it sanitary.
B or C could then be interfaced to an arduino and run to a computer and output a CSV file which excel could read. Run a few macro's in excel, and Bamm, for 35$ + either 20$ or 1$ (potentiometer or strain gauges) plus some mounting equipment, you have a modular digital hydrometer that can do easy data logging.
let me know if im missing something and ill go back the the drawing boards.... if not, im gonna try and build one of these after i finish my masters thesis haha...
use an arduino development board and you could control and interface 15 digital signals for 35$ (cost of board + usb connector to computer interface).
As for the actual measuring, i had a few ideas... ive thought about this extensivly, and i guess the first unknown which my ideas are based off of would be could you assume a sight glass in your fermentor/mash tun/keggle/etc. there are two possible methods you could use. If you had a closed loop sightglass (to prevent oxidation of course) you could simply
a) place a hydrometer in that and just read it....
b) make something hydrometer shaped... maybe a testtube or the like. and place a Potentiometer on the outside of the sightglass. you put something ferrious in the testtube, and as it moved up and down, like a hydrometer, it would electronically register on the potentiometer... an analog version of reading the numbers on the hydrometer.
c) tether a float to the bottom and attach a strain gauge to the line. The strain gauge would register high resistances (when strained) for low SG and low resistances (when un-strained) for high SG. you could place this float in a bracket of some sorts, and you could make it movable instead of permanent mounting. Strain gauges are linear over most of their range, so you would only have to make it sanitary.
B or C could then be interfaced to an arduino and run to a computer and output a CSV file which excel could read. Run a few macro's in excel, and Bamm, for 35$ + either 20$ or 1$ (potentiometer or strain gauges) plus some mounting equipment, you have a modular digital hydrometer that can do easy data logging.
let me know if im missing something and ill go back the the drawing boards.... if not, im gonna try and build one of these after i finish my masters thesis haha...
bricklayer38
Member
I am new to homebrewing. On Sunday I broke my hyrometer and cut my hand, blood everywhere, pretty nasty. I googled hydrometer and this thread popped up. I would gladly pay to have something safer and easier to read. Baron, Any progress on this?
camiller
Well-Known Member
Don't know if Baron has pursued this but do a search on refractometer for something that is safer and pretty easy to read.
smmcdermott
Well-Known Member
I too would be interested in this, more of a simple one for me, but it seems like there is no progress. Let us know what the deal is...
bricklayer38
Member
Cool, I will check out the refractometer idea. Also, I found this website -sounds like exactly what I want. Anybody know anything about this?
http://fermonitor.com
http://fermonitor.com
Sawdustguy
Well-Known Member
It looks like someone came up with a sensor back in 1990 but nothing ever came of it:
Date: Thu, 5 Apr 90 10:21:10 PDT
From: c9a-aa at dorothy.Berkeley.EDU (Todd Matson)
I submitted this file a couple of weeks ago, but I don't think it was
ever posted. I have talked to some large brewers, and they have been
responsive, but I am having trouble getting feedback from home
brewers. If you can not post it for some reason, please send me a note.
Subject: Digital Hydrometer
Researchers at UC Berkeley have developed a small, inexpensive sensor that
can measure the density of a liquid. I have learned that such a device
would be useful for home brewers to measure the specific gravity of a
fermenting wort or must. If home brewers are responsive, my group would
consider producing a digital density sensor and marketing it through home
brew shops and clubs.
The hydrometer will consist of a small box with a digital display that
contains the necessary electronics. A switch will select the active sensor
(the hydrometer will accept input from as many as four sensors). Each sensor
will be the size of a toothpaste cap and will be attached to one end of a
six foot wire (the other end of the wire will plug into the box). The wire
will be inserted into the carboy through the stopper. The sensor will remain
in the brew throughout fermentation and the display will be updated
continuously. Thus, measuring the density will be convenient and will
introduce no risk of infection. We anticipate that the hydrometer will be
sold with one sensor, and that additional sensors will be sold separately.
I would like some feedback: Are people interested in a digital hydrometer?
If so, please give me an idea of what you would pay for such a device. If I
get a good response from home brewers, my colleagues and I will certainly
proceed with the project.
Todd Matson / c9a-aa at dorothy.berkeley.edu
Date: Thu, 5 Apr 90 10:21:10 PDT
From: c9a-aa at dorothy.Berkeley.EDU (Todd Matson)
I submitted this file a couple of weeks ago, but I don't think it was
ever posted. I have talked to some large brewers, and they have been
responsive, but I am having trouble getting feedback from home
brewers. If you can not post it for some reason, please send me a note.
Subject: Digital Hydrometer
Researchers at UC Berkeley have developed a small, inexpensive sensor that
can measure the density of a liquid. I have learned that such a device
would be useful for home brewers to measure the specific gravity of a
fermenting wort or must. If home brewers are responsive, my group would
consider producing a digital density sensor and marketing it through home
brew shops and clubs.
The hydrometer will consist of a small box with a digital display that
contains the necessary electronics. A switch will select the active sensor
(the hydrometer will accept input from as many as four sensors). Each sensor
will be the size of a toothpaste cap and will be attached to one end of a
six foot wire (the other end of the wire will plug into the box). The wire
will be inserted into the carboy through the stopper. The sensor will remain
in the brew throughout fermentation and the display will be updated
continuously. Thus, measuring the density will be convenient and will
introduce no risk of infection. We anticipate that the hydrometer will be
sold with one sensor, and that additional sensors will be sold separately.
I would like some feedback: Are people interested in a digital hydrometer?
If so, please give me an idea of what you would pay for such a device. If I
get a good response from home brewers, my colleagues and I will certainly
proceed with the project.
Todd Matson / c9a-aa at dorothy.berkeley.edu
dozer4412
Well-Known Member
I really hope something comes of this. Some really cool monitoring could be done if this product does what its claiming to.
Have you tried to contact Todd Matson? That thing sounds *awesome*.
dozer4412
Well-Known Member
Looks like this would do the trick. Problem is I'm sure it's pricey. Would be nice to find just the raw sensor off something like Digikey and make a DYI sensor or logger with an micro-controller. I was unable to find anything, but didn't spend long looking.
http://www.densityanalytics.com/
http://www.densityanalytics.com/
camiller
Well-Known Member
He is a member here. Here is a thread with an update as of yesterday.
https://www.homebrewtalk.com/f11/fermonitor-lives-93194/
Erroneous
Well-Known Member
Really sorry to bring up an old thread but since I can't seem to find any recent news on Fermonitor, looking at the description for
it seems that this is just a cylinder (probably sealed) with a hall sensor on one end, float on the other and spring between them. Or a float on top, weight on bottom and spring in the middle. Calibrate the float/weight and spring well enough and you have a simple digital hydrometer. Anyone try this or something similar?
it seems that this is just a cylinder (probably sealed) with a hall sensor on one end, float on the other and spring between them. Or a float on top, weight on bottom and spring in the middle. Calibrate the float/weight and spring well enough and you have a simple digital hydrometer. Anyone try this or something similar?
I will be working on a project for school that will include a data logging digital hydrometer. My current plan is to use a stainless steel object of known weight and volume immersed in the beer, and attached to a strain gauge. Using Archimede's Principle the density of the beer can be calculated based on the weight of the object in beer. Whether or not this works will depend greatly on the sensitivity of available affordable strain gauges (or whatever else I may be able to use to measure weight). I've gone through a number of different ways to approach the problem of automatically measuring SG over time while collecting data, and this seems to be the best approach thus far.
It will be a while before I have any more concrete information on the project, so don't get your hopes up yet! :cross:
russellqwerty
Member
Keep us posted on that
What about using a digital refractometer sensor? I am very happy with my Milwaukee digital refractometer (~$110) and would be even more happy if the sensor was in my conical and connected to somthing like my BCS460 controller for monitoring, logging and control.
This would allow me to monitor fermentation temp and gravity remotely. :rockin:
I'd see paying $150 - $200 for a probe that could be mounted in my conical and interface with the BCS controller.
http://www.milwaukeetesters.com/MA871.html
http://www.embeddedcontrolconcepts.com/
The magic is in making the probe affordable, all the other jive is already done.
This would allow me to monitor fermentation temp and gravity remotely. :rockin:
I'd see paying $150 - $200 for a probe that could be mounted in my conical and interface with the BCS controller.
http://www.milwaukeetesters.com/MA871.html
http://www.embeddedcontrolconcepts.com/
The magic is in making the probe affordable, all the other jive is already done.
LordUlrich
Well-Known Member
I have been working on something very similar for a brewery automation project (because i can, and like to learn)
So far I have run some calculations for using copper pipe for a weight, and low cost hanging scale (stripping the sensor out) would give me reasonable accuracy (0.01 SG), at this point i am looking at using it in the boil kettle to set boil off to hit my OG....i have yet to find a way to compensate for the bubbles though i have a work around for my situation.
I was looking at <$50 for the sensor, and everything else will tie into my control system (embedded ardunio thing)
russellqwerty
Member
I'm also workign on an embedded sensor to use with an arduino. Likewise, I want it to be a cheap way < 50 to do so. There should probably be a new thread on this to reduce redundancy
https://www.homebrewtalk.com/f51/digitial-hydrometer-sensor-267405/
