My Keg Volume Solution

[MartyA]

Hi folks. I'm posting to show off my keg volume solution. This may be overkill for those of you who judge by the seat of your pants, but if you want hard data about volume this could be what you want.

The pic shows the display unit. In my case it's permanently mounted in a wall plate behind the kegerator. There's also a proximity sensor that allows the backlight to be dimmed when no-one is near the keg and a wall wart that powers the unit. The whole thing is small enough to mount in an external box also.

The two circles below the display are buttons that control the menu that allows resetting the keg size and resetting for a new keg.

The glass in the foreground shows the pour - you can see that the reported volume is dead on with the pour. After pouring a full half barrel the keg showed zero about half a liter before it blew air.

The volume measurement is based on a flowmeter, so there's no calibration - it will show exact pours from the time it's hooked up. To get useful keg information you have to reset it with a full keg.

I'm happy to answer general questions in responses. If you want specifics, feel free to email me directly.

Marty

[dcoult]

I'm really interested to see what you've worked up. Will you post details up here?

[MartyA]

Glad you like it

To tell the truth, I'm thinking about selling these, so I'd prefer not to get into the details of the implementation, but I can tell you that the core technologies are a flowmeter and a microcontroller. I'm considering including temperature and pressure measurement as well, but inexpensive pressure sensors that work in a liquid environment are hard to come by.

Thanks for your interest, and feel free to send a private message if you'd like.

[JBUNGIE]

Would this worked for multiple keg setups? Pretty cool stuff..

[MartyA]

In short, yes, multiple kegs would work

My current implementation only uses a single flow sensor, but the hardware I'm using could support up to 6 sensors. I can't imagine a home user would ever have that many active kegs, but it could be supported.

On the software side, I anticipated tracking multiple kegs, but to make that functional will require more work. One change that would likely be needed would be to support custom keg sizes - right now I have a fixed list of half-barrel, quarter barrel, corny (5 gal), and euro (50 liters). Letting the user input a custom amount would accommodate home brewers who end up with an odd amount of beer, but would be hard to do with just two buttons. I haven't gone past thinking about this as I'm not doing home brew, just purchasing kegs.

One big limitation is the display - 2 lines of 16 characters is pretty limiting. I've considered moving to a 4x20 line display, but then you almost have too much space - what else would you want to know?

And there is one other concern - cost. The flow sensors are the single most expensive component, and while they aren't physically huge, they do take some space and they must be mounted vertically to avoid trapping air bubbles. I have mine mounted in the tower right before the tap which works well, but there wouldn't be room for more than one in a typical tower.

So that's the long answer. As a ballpark number, would you buy this with one sensor for $200? With an additional $50 to $75 for each additional sensor? That's not cheap, but that's the real question I need to answer before I actually commit to producing some for sale.

[Sketch]

As a home user I would say no. Spending $200 on an unnecessary gadget just doesn't seem reasonable.

By no means am I saying your design isn't very cool, it's just not something I would spend that much on. The amount of beer in my keg isn't important enough to me, especially when I can give it a quick tilt to get a rough gauge of the percentage remaining.

[MartyA]

Yes, that's what I was afraid of

Thanks for your feedback, Sketch. Your comments are exactly what I was concerned about.

On the other hand, if you're already laying out 500 to 1000 (+) for a kegerator, this is a not-unreasonable amount. And particularly if you're pouring multiple kegs, having some knowledge of the contents is worth something.

[Kozeman]

$100 I would buy for sure. $150 I would have to think about. I was also considering a remote display scale from office max that lets you zero out the weight of a package (keg) and put the display/controller outside the fridge. That runs $150 for the 400lb capacity model. This technique is a little less invasive if the scale is ok with the temperature. Cool idea though.

[bkl63]

At that pricing I would peg your market as more along the lines of commercial establishments and it would be inline for that environment. It would need to be key reset capable for that market where they are looking towards shrinkage issues.

A home version to be successful would probably need to be under $100.00 and the lower you can get below that the more success you would have.

Not knowing much about what you are using, some important things to me would be Stainless Steel, Easy to clean, reliability, accuracy and ease of use.

For a commercial application, secure key for reset.

[cubby_swans]

I wouldn't bother with custom input volumes. As a homebrewer, I've made and drank enough beer that I have a pretty good idea how much beer is left by the feel of my keg. Also, someone that's that into beer is 99 percent likely to have either standby kegs of homebrew or bottles that it's just not worth it to buy a gadget to tell me what I am pretty close to already knowing. Besides that, when I brew a batch, I really have no clue if I have 4 1/2 gallons or 4 3/4, etc, without physically weighing the keg, so then I'd need another piece of equipment to give me accurate readings on weight to determine that custom beer level in the first place.

Not worth the effort, IMO. If you start selling this software, maybe include updates, and if you get feedback requesting a function like this, give free updates.

Your fixed list of kegs should include 1/6 barrels. They're quite common. Close in volume to a corny, but if you're going to want people to spend $200 on something like this, I don't think 'close enough' is going to cut it.

I think a HUGE selling point to something like this might be for it to have the ability to record and recall a history of pour volumes. Retail accounts would LOVE to make sure their bartenders are pouring the correct amount.

[bkl63]

To add to this...

20 liter and 30 liter are two further commercial sizes (thought very close to 1/6 and a 1/2 in volume).
50 liter is also called 13.2 gallons by some.

Your fixed list of kegs should include 1/6 barrels. They're quite common.

[psychodad]

I'm not knocking the project because it does have a high coolness factor However the Smartstrip is way cheaper. In the end though, I go pretty good at judging when my commercial kegs were going to blow and now if I have a corny go empty, I have one already carbed and cooled to take its place.

I'd suspect a large bar wouldn't have a need for these either as they should know what sell and when to order kegs so that a replacement is available when needed.

Long story short, $200 will buy a Smartstrip and a lot of beer.

[MartyA]

Wow, great feedback!

Thanks again to everyone for your suggestions and feedback.

As to the price, I'd agree that getting under $100 would be a great target. On the other hand, there's several consumer-grade devices that are under $100, but use significantly inferior sensing technology. I'd hope that the better results are worth a higher price, but how much is the question

Moving to mass production would also lower the price significantly and I'm exploring that as well.

As for adding additional keg sizes, that's a trivial change and your suggestions are good ones. Because of the high accuracy of the flow meter, having an exact amount is valuable.

As far as cleaning, the sensor itself is plastic and won't be affected by cleaning solutions. Since you're likely to be cleaning between kegs the reset on putting in the new keg will take care of the liquid flow during cleaning. Alternatively, just unplugging the unit while cleaning will let it ignore that liquid flow while not losing the data to that point.

Anyway, thanks again for your feedback! And good pouring to everyone

[washingtonbc]

Home Page

keg meter *** com

I just ordered one. I'll report about it in a few weeks, (or kegs).

BC

[Fastsc92]

I've been contemplating getting the keg-o-meter for a little while now. I believe instead of using a flow-meter, it uses a pressure transducer. When it senses a drop in pressure, it begins an internal timer. So a first time calibration is required, (10 seconds resulted in 12oz of beer, etc). Then the controller can always calculate the amount beer that was poured. It's not as accuarate as a true flow meter, but it'll get you in the ball-park. I'm pretty sure that's how the price is around the $100 mark. I may give it a try. I'm deciding between this, or a dual tap set-up to spend my money on. Decisions, decisions.........