# Keg Weighing System



## punkin (15/2/13)

I'm trying to find the you tube vids i saw linked on here ages ago of what i think was a kiwi guy who installed scales in his keezer and could measure how many pinys he had left in a keg.

I tried a search and came up with nothing, does anyone (most probably) have a better memory as to where it may have been and could in a perfect world provide link to the thread or the video?


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## MastersBrewery (15/2/13)

check the arduino thread system was built by Zizzle, took him a good while to get it going though, think he used sensors from a bathroom scale them amplified the signal. Will see if I can find the thread. Tutorial required if you build it though!!!


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## MastersBrewery (15/2/13)

ok I was wrong but here's the linky http://aussiehomebrewer.com/topic/68935-keggerator-upgrade-beer-level-indicator/#entry973603


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## punkin (15/2/13)

Excellent thank you. I seem to recall he did a good job of a tutorial in the original post?

Not gunna build it, would make it too easy for her to track what i drink in a session and would probably scare the life out of me too.


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## PeteQ (15/2/13)

I've thought about this idea for a while, unfortunately I'm not an electronics and/or IT genius so I'm slowly getting bits together for this project with coding help from a mate.

This is definitely worth a look if you haven't seen it already http://kegbot.org/


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## punkin (15/2/13)

This looks terriffic. Does anyone here run this?


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## MastersBrewery (15/2/13)

PeteQ said:


> I've thought about this idea for a while, unfortunately I'm not an electronics and/or IT genius so I'm slowly getting bits together for this project with coding help from a mate.
> 
> This is definitely worth a look if you haven't seen it already http://kegbot.org/


those flow sensors look like they could be used else where in the brewery too, food grade and good for 90c+ only thing is the price at $60 each could get a little pricey.



Edit: typo


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## Nick JD (15/2/13)

Heh heh, keg bot.

I was thinking two weldless fittings on the top and the bottom of the side of a keg with some beer line between them. But I'm a simple chap.


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## MastersBrewery (15/2/13)

I think it's just easier to have a few full kegs as back up. Kegbot looks like it's doable well atleast for some of our more tech minded, but the board they sell only handles 2 taps on a normal arduino to go to more Taps requires you to have a board made (they have the files freely avaliable), and an ardunio mega, software would be the same as the code can handle 6 taps. All that I could do, I just wouldn't know where to put what parts once I had the boad made. I have 3 Taps so I recon $100 a tap, the other positive would be once put together and sorted adding a tap would be $60 + postage for the flow metre.


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## punkin (16/2/13)

Lost my reply. Somone on another forum pointed me to this system.

At least it's plug and play and whole lot less expensive. You loose the accuracy and all the extra features though.

Not sure it's worth the effort if it's out 10 glasses a keg.

http://www.keg-meter.com/


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## Edak (18/2/13)

MastersBrewery said:


> I think it's just easier to have a few full kegs as back up. Kegbot looks like it's doable well atleast for some of our more tech minded, but the board they sell only handles 2 taps on a normal arduino to go to more Taps requires you to have a board made (they have the files freely avaliable), and an ardunio mega, software would be the same as the code can handle 6 taps. All that I could do, I just wouldn't know where to put what parts once I had the boad made. I have 3 Taps so I recon $100 a tap, the other positive would be once put together and sorted adding a tap would be $60 + postage for the flow metre.


Wait.. I thought that you could have 4+ taps with a single Arduino uno. Where did you get that info?


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## MastersBrewery (18/2/13)

Edak said:


> Wait.. I thought that you could have 4+ taps with a single Arduino uno. Where did you get that info?


Read through the forums a little, One keg board and an arduino uno can do 2 taps max, each keg board can take 2 coasters max, and each coaster can run 2 taps, but apparently the coasters were only for convinience of wiring. It comes down to the number of interupts avaliable on the arduino. Now you can hook up as many arduino's with kegboards up to the same system as you like (just rename server side). The Arduino Mega (and they reccomend the AT128) can handle upto 6 taps but as stated previously you would have to have the board made up yourself. Note the server for keg bot does not run on the arduino it requires a seperate linux system, and if you want the interface obviously a cheap Andriod tab. Still got a bit more reading to do, I have nowhere near the arduino experience you do, you might be able to get your head around it a little better. If I were to do something like this it would be a few years down the track, so hopefully one of you guys get one up and running and I can pick your brains. Over all it seems well documented and the forums provide a little more indepth info.

Edit:
Ummm .... pics or it didnt happen, nah bugger that, anyone does this and they should do a tutorial very cool bit of kit


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## dmac80 (18/2/13)

If you're after accurate volume measurements, i think Zizzle's method of weighing the keg would be more accurate than flow measurement. 
When you try and totalise a flow, if there are any inaccuracies in the flow measurement these are 'amplified' by the totalising. The error then becomes quite noticeable.
Cheers
Dan


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## dougsbrew (18/2/13)

worth considering? linky - http://www.ebay.com.au/itm/Digiflow-Digital-Flow-Meter-count-up-total-Water-Measure-in-Gallons-GPM-56-cable-/350693774919?pt=LH_DefaultDomain_0&hash=item51a6fa5647


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## dmac80 (18/2/13)

There doesn't appear to be any accuracy data on that listing doug, maybe ask the seller. Then you can work out your maximum error over the volume of a keg.
Cheers


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## punkin (18/2/13)

That's the one in use by people on a forum where they are measuring flow of cooling water. They are very happy with the unit, but accuracy is claimed to be +- 5%.

Looks like if you want usefull accuracy you need to pay the bickies.

http://www.digisavant.com/PDF/DF0671L-Spec.pdf


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## MastersBrewery (18/2/13)

dmac said:


> If you're after accurate volume measurements, i think Zizzle's method of weighing the keg would be more accurate than flow measurement.
> When you try and totalise a flow, if there are any inaccuracies in the flow measurement these are 'amplified' by the totalising. The error then becomes quite noticeable.
> Cheers
> Dan


Zizzles system is measuring in pints, and using amplifiers to boost signal, the keg bot can measure in mls with accuracy +/- 1% straight off the shelf, if the calibrated to the system +/- 0.3% so that'd be like 60ml over a keg. The other thing is comparatively keg bot is plug and play. Zizzle has awesome coding and electronics skills that make the rest of us look like dopes, and it took him a year, so for someone like me to build a unit to do what these systems do from scratch would be counter intuitive, why would I reinventing the internal combustion engine with no idea of egineering.

I think zizzles system is friggin awesome, but I couldn't replicate it.

Keg bot is also awesome and something with help I could implement, it also has a few extra nifty features already built in.


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## Edak (18/2/13)

MastersBrewery said:


> Read through the forums a little, One keg board and an arduino uno can do 2 taps max, each keg board can take 2 coasters max, and each coaster can run 2 taps, but apparently the coasters were only for convinience of wiring. It comes down to the number of interupts avaliable on the arduino. Now you can hook up as many arduino's with kegboards up to the same system as you like (just rename server side). The Arduino Mega (and they reccomend the AT128) can handle upto 6 taps but as stated previously you would have to have the board made up yourself. Note the server for keg bot does not run on the arduino it requires a seperate linux system, and if you want the interface obviously a cheap Andriod tab. Still got a bit more reading to do, I have nowhere near the arduino experience you do, you might be able to get your head around it a little better. If I were to do something like this it would be a few years down the track, so hopefully one of you guys get one up and running and I can pick your brains. Over all it seems well documented and the forums provide a little more indepth info.
> 
> Edit:
> Ummm .... pics or it didnt happen, nah bugger that, anyone does this and they should do a tutorial very cool bit of kit


Yeah, it appears you are right. The website is misleading but the forums describe it perfectly. For four taps you have to either:
1. buy two arduinos, two keg boards and two coasters
2. buy arduino mega, design own keg board and two coasters
3. re-design the wheel

Personally that sounds like too much hardware.



dmac said:


> If you're after accurate volume measurements, i think Zizzle's method of weighing the keg would be more accurate than flow measurement.
> When you try and totalise a flow, if there are any inaccuracies in the flow measurement these are 'amplified' by the totalising. The error then becomes quite noticeable.
> Cheers
> Dan


Zizzles method is great but it requires a LOT of work:
* Build custom floor for the fridge to which you can bolt the measuing apparatus
* Build the measuring plates
* Ensure that your floor and plates aren't going to get destroyed by condensation/liquid damage
* Calibrate each measuring plate
* Build the amplification circuit
* Ensure shielding is strong
* Much more wiring


I am thinking that I will use a purpose-built data logger which can handle everything and has a webserver in-built. I already have a suitable solution with multiple high-speed counters and inputs for up to 5 load cells, but I still like a proper, customised solution.


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## dmac80 (18/2/13)

MastersBrewery said:


> Zizzles system is measuring in pints, and using amplifiers to boost signal, the keg bot can measure in mls with accuracy +/- 1% straight off the shelf, if the calibrated to the system +/- 0.3% so that'd be like 60ml over a keg. The other thing is comparatively keg bot is plug and play. Zizzle has awesome coding and electronics skills that make the rest of us look like dopes, and it took him a year, so for someone like me to build a unit to do what these systems do from scratch would be counter intuitive, why would I reinventing the internal combustion engine with no idea of egineering.
> 
> I think zizzles system is friggin awesome, but I couldn't replicate it.
> 
> Keg bot is also awesome and something with help I could implement, it also has a few extra nifty features already built in.


The listed 1% accuracy doesn't specify if it is 1% of measurement or 1% of full scale (which can often be the case). 1% of full scale will give a much larger error. Having said that, the flow meter listed looks a good bit of equipment.



Edak said:


> Yeah, it appears you are right. The website is misleading but the forums describe it perfectly. For four taps you have to either:
> 1. buy two arduinos, two keg boards and two coasters
> 2. buy arduino mega, design own keg board and two coasters
> 3. re-design the wheel
> ...


 I think both of you guys have kind of missed my point, i'm not saying to go out and try and build Zizzle's setup, but from my experience working on instrumentation in industry, it's more accurate to measure the product in a vessel than to try and totalise the flows in or out.

The kegbot certainly does look like a flash bit of gear though!

Cheers
Dan


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## Nick JD (18/2/13)

What about a temperature sensitive sticker that goes down the side of the keg. You open the fridge for a minute, and you can see where the fluid level is due to the empty part of the keg warming faster than where the beer is.

50c per keg.


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## slash22000 (18/2/13)

Nick JD said:


> What about a temperature sensitive sticker that goes down the side of the keg. You open the fridge for a minute, and you can see where the fluid level is due to the empty part of the keg warming faster than where the beer is.
> 
> 50c per keg.


Yep. This is what I use.

The geek in me likes the idea of a computer that could accurately measure the beer left in the keg, but the lazy in me means I couldn't be fucked unless it's a "plug and play" type deal and doesn't cost a thousand bucks.


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## stux (18/2/13)

I just give the kegs a bit of a tug... if it moves up, then its nearly empty 

funnily enough the same 'system' works on my pool chemical barrels (auto-feed system)


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## MastersBrewery (18/2/13)

Edak said:


> Yeah, it appears you are right. The website is misleading but the forums describe it perfectly. For four taps you have to either:
> 1. buy two arduinos, two keg boards and two coasters
> 2. buy arduino mega, design own keg board and two coasters
> 3. re-design the wheel
> ...


The have a keg board designed to fit the Mega, they just dont produce it, so simple down load and send it off for fabrication.


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## jayahhdee (18/2/13)

Nick JD said:


> What about a temperature sensitive sticker that goes down the side of the keg. You open the fridge for a minute, and you can see where the fluid level is due to the empty part of the keg warming faster than where the beer is.
> 
> 50c per keg.


50c a sticker? any links to similar products on ebay? I was looking at getting some of Keg Volume Stickers but I think the price is a bit much.


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## Edak (18/2/13)

Thinking about it further, you could have a bunch of hardware counters going into a shift register, then you could read that shift register serially with arduino, as long as the arduino can service these quickly enough then you can have many flow sensors connected via one serial interface (with one enable line per flow sensor to put counter into Z state). 


SN74HC590AN --->

SN74HC590AN --->
SN74HC590AN ---> CD4021 ---> Arduino digital inputs

SN74HC590AN --->

I think that the nominal frequency output during a pour would be 500Hz (based around 6100Hz/L and about 6 seconds to pour a pint) and each counter has 256 states so you need to read each within 0.5 sec to prevent overflow.

OR!!!!

Use one of these chips for each flow meter (32bit counter > SPI Serial interface), which means you have no read time issues and only require one chip to talk to your arduino using the existing SPI interface. This would be the BEST solution!
http://www.anaheimautomation.com/products/ics/lsi-csi-item.php?sID=270&serID=17&pt=i&tID=159&cID=55


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## MastersBrewery (18/2/13)

Edak said:


> Thinking about it further, you could have a bunch of hardware counters going into a shift register, then you could read that shift register serially with arduino, as long as the arduino can service these quickly enough then you can have many flow sensors connected via one serial interface (with one enable line per flow sensor to put counter into Z state).
> 
> 
> SN74HC590AN --->
> ...


hmmm, think I know where your going, but it's like the whole zizzle thing, I seriously think you two could talk this stuff for hours and of course empty the keg being counted. I can solder, I can drill, upload software to devices, I've even had a linux server. (with help) But alot of this stuff goes way over my head. Electronics and programing and me, well we have an understanding, Me: "please work" the electeonics etc .... well they do what they like. Just to ensure I haven't got you wrong; your going to shift the flow sensor inputs from the serial bus by having another chip convert it to digital. Or am I somewhere looking for the wrong star gate.


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## Edak (19/2/13)

MastersBrewery said:


> ... Just to ensure I haven't got you wrong; your going to shift the flow sensor inputs from the serial bus by having another chip convert it to digital. Or am I somewhere looking for the wrong star gate.


The flow signal is already technically digital (pulses) but the first counter chip translates it to a binary number that represents the number of counts (eg. 0100 1001 = 73). The problem is that each bit is in parallel so each sensor requires at least 8 digital lines. Now we don't have 32 digital inputs on the arduino (8 digital lines x 4 flow sensors) so we use a separate chip (shift register) to convert those 8 separate lines to a single, serial line. We can get away with using one shift register to save on build cost and less data lines by allowing it to switch between which sensor it reads parallel data from.

Or, you could forget all the above and use the second chip solution that I mentioned with SPI built in, one chip per flow sensor, no timing constraints either. Four chips on a shield and plug and play.

If anyone has CPLD experience then we could also look at halving the cost of the chips by using a CPLD instead...
http://ad7gd.net/counter/


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## PeteQ (19/2/13)

Edak said:


> Zizzles method is great but it requires a LOT of work:
> * Build custom floor for the fridge to which you can bolt the measuing apparatus
> * Build the measuring plates
> * Ensure that your floor and plates aren't going to get destroyed by condensation/liquid damage
> ...


Edak

Do you believe that flow sensors would be the best way to achieve keg level monitoring? The flow sensors that the kegbot use are $60 plus delivery each. Is this what you would intend on using if you were to go ahead with this project?

I was really hoping Zizzle's idea would be the way to go based only on the cost. I believe we could get it way under $100 for the whole system.

I've already started doing some extremely basic coding for a simple keg weighing system that will most likely display the % of whats left in each keg which is totally dependent on whether I can sort out the electronics side. There are a few load cell tutorials online so hopefully this won't be a problem...


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## MastersBrewery (19/2/13)

PeteQ said:


> Edak
> 
> Do you believe that flow sensors would be the best way to achieve keg level monitoring? The flow sensors that the kegbot use are $60 plus delivery each. Is this what you would intend on using if you were to go ahead with this project?
> 
> ...


My prob with this would be my kegs aren't all the same or even the same volume, so each keg would have to have it's own individual schema


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## Edak (19/2/13)

I believe that the flow system should give you a very accurate result, even if you have +/-1% accuracy that's less than a pot. 

It just depends on where you want to spend your time, either building mechanical things and going through a lot of trial and error, or use a sensor that's easy to install and proven to work by others. What load cells do you have and how do you plan on attaching them to weigh your keg? Do you have a diagram of how it will work?


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## PeteQ (19/2/13)

I still dont have any load cells, but i do have some instrument amplifiers on the way. I'm hoping to use load cells from some cheap digital scales as per Zizzle's setup.

After further investigation it looks like Matho has done it as well - http://aussiehomebrewer.com/topic/41443-hlt-controller/page-2

Also on the bottom of that page Zizzle mentions this article and the instrument amplifiers I'm waiting on - http://www.ehow.com/how_5980113_make-load-cell-use-arduino.html

Definitely not sure if any of this will actually work, hit and hope i guess...


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## Edak (19/2/13)

Just found another kegerator weight build from years ago...

http://kegmonitor.webs.com/letsbuildit.htm

He uses the sparkfun load cells (the same as the ones in your bathroom scales. 
You still need a stable platform to put each keg on though.


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## punkin (19/2/13)

I would be very interested if someone was to build a kit in the flow sensor type that worked for a tap system. I guess i would shell out for the better sensors at $60 if the rest of it came in a plug and paly box that was a reasonabe price. I would not be interested in a weighing system for myself.

Kegbot really does look the ant's strides.


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## MastersBrewery (19/2/13)

punkin said:


> I would be very interested if someone was to build a kit in the flow sensor type that worked for a tap system. I guess i would shell out for the better sensors at $60 if the rest of it came in a plug and paly box that was a reasonabe price. I would not be interested in a weighing system for myself.
> 
> Kegbot really does look the ant's strides.


I agree


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## PeteQ (19/2/13)

Edak,
The intricacies of the build will come way later on down the track. I do like playing around with things and if i can get this project working I'll be stoked but for now I'll just take it one step at a time. I was hoping if i get stuck I would bank on you guys to help me out!

Masters
I have already sorted out code for a keg zero system for each keg on each load cell so it knows the starting weight of the keg prior to racking. I'm unsure whether to do the same thing full, I'll have to see how well the load sensors work. BUT one thing I didn't think of with the kegbot is what if your keg isn't full from the start? Do you somehow calculate the amount of beer that goes into the keg when racking maybe with another flow sensor? I'm going to look into this....

Don't get me wrong, the kegbot is frieken awesome but the price is pushing me towards something a little, well, a lot cheaper. To install a kegbot on my 4 tap keezer would cost over $300, certainly money I don't have lying around for something I don't really need....


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## DavidP2190 (19/2/13)

I saw this thing yesterday and wondered if it could be used for measuring keg levels somehow, I don't keg myself but it may be worth a look.

http://www.jo3ri.be/arduino/blogduino/arduinodualtanklevelmeasuringhasbeenupdated
and an instructable here:
http://www.instructables.com/id/Arduino-dual-ultrasonic-liquid-level-meter-with-in/#step1


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## jacknohe (19/2/13)

I looked into options to identify how much was left in the keg. Would be cool with a digital display for "Brew Porn". But I just tap the side of the keg with my finger going from the top and moving down. As soon as the sound changes to a lower note, I know where the level is.


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## MastersBrewery (19/2/13)

I think as punkin said , if someone comes up with a system that works and can, do a similar thing to what matho did with the braumiser I am dead set certain you'd have a line up of takers, most of us just don't have the electronics and coding skills to pull something like this off. So next best is kegbot.... but as stated throughout this thread it'll cost a bit.

and Yes it's all about the bling, but useful bling


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## MastersBrewery (19/2/13)

If I had the skills thishttp://www.ebay.com.au/itm/ARM9-Board-1G-NAND-Flash-mini2440-S3C2440-7-TFT-LCD-Touch-Screen-/200778761178?pt=LH_DefaultDomain_0&hash=item2ebf58c3da is what I'd run it from and the server and prolly the ferment/cc fridges Has plenty of IO's to play with.


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## punkin (25/2/13)

Is anyone still thinking of taking on this project using the kegbot?

I'd be very interested if someone was to build an extra. I have a 4 tap kegerator.


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## MastersBrewery (25/2/13)

punkin said:


> Is anyone still thinking of taking on this project using the kegbot?
> 
> I'd be very interested if someone was to build an extra. I have a 4 tap kegerator.


It's on the wish list, but have a few other projects to finish off first, so not in this years plan. I would go the atmega as I have more than 2 taps, so if some one was to do a run of boards I'd definitely put my hand up. Obviously the expensive p[art of this is the sensors, so they would probably wait. Setting up the rest of the system, and having it communicate with server and Android and ironing out bugs would be the bulk of the job done with out huge outlay.

so in short someone do a mega board run!
https://github.com/Kegbot/kegboard/tree/master/hw/kegboard-mega


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## Edak (25/2/13)

I think that it's a bit expensive for kegbot but I am still looking into other options.


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