Keg Scale and Digital Tap List project

[megabyte]

An update... I was thinking about alternatives to weighing the kegs for situations where a scale wouldn't be practical and I wondered if I could use an infrared distance sensor to measure the distance from the keg lid down to the top of the beer. Here's a new video I put together showing the experiment and the results.

https://www.youtube.com/watch?v=IPW7vWlXodk

Enough distractions now, I gotta get back to programming and building a better looking prototype!

 

[peteru]

I was also pondering other methods and an ultrasonic distance measure or even a sonar like echo came to mind. The sonar method should work with an external transducer, but I wonder if the characteristics are likely to change with each keg and even with the state of the contents, such as level of carbonation.

One could waste months and $$$$ toying with such ideas.

 

[Bomber Watson]

I will be extremely happy to pay money dollars foe this once done.

Edit, just having a bit more of a think.

Are you currently working on a proper prototype loadcell, then going through pricing then starting a kickstarter or similar?

Easyest way to cover some of the development cost I think, just have a basic package with one scale then increasing packages ontop of that up to say 10, boom done.

My other thought, now I'm about as tech savvy as a cave man, but I was thinking a dedicated monitor mounted behind the font would be nice.

22" or so lcd monitors can be had for the spare change in your ash tray now days.

What kind of doohickey white mans magic thingy would be needed to pick up the Bluetooth from the scales, hold the app and send it to the monitor? Or is that harder than o thought?

 

[megabyte]

My other thought, now I'm about as tech savvy as a cave man, but I was thinking a dedicated monitor mounted behind the font would be nice.

22" or so lcd monitors can be had for the spare change in your ash tray now days.

What kind of doohickey white mans magic thingy would be needed to pick up the Bluetooth from the scales, hold the app and send it to the monitor? Or is that harder than o thought?

Thanks for the tips! For adding an external tv screen I was thinking of supporting tvOS in the app so you can use it with an Apple TV. There are android TVs too so running a native app on the TV might be an option, it's hard to work out what level of BLE compatibility these devices have though. I must admit I haven't ventured too far down this path yet.

 

[boybrewer]

Does no one else just tap their kegs and listen to the pitch?

It varies with pressure, and the height of the liquid. So since we all have different serving pressures it's not as nice as a loadcell, but after a bit of experience it works well to someone with a musical ear.

This method was used in old filling height measurements in industrial bottling lines - and the brand is still around - "Taptone". They don't use this method anymore though as machine vision blows it out of the water.

Some people have limited hearing and might not be able to hear those type of nuances .

 

[mstrelan]

An update... I was thinking about alternatives to weighing the kegs for situations where a scale wouldn't be practical and I wondered if I could use an infrared distance sensor to measure the distance from the keg lid down to the top of the beer. Here's a new video I put together showing the experiment and the results.

Can you float some sort of sanitised stainless steel ball on the top of the liquid? Would the sensor need to be aimed directly at the ball or is the detection range fairly broad?

Or can you make the sensor waterproof and point it up to the lid instead of down from the lid?

 

[contrarian]

If you were going to use a float wouldn't it be easier to run it up and down a post of sorts and measure the height mechanically?

It wouldn't need to be rigid, some kind of food grade string or wire with a weight at the bottom and I would be surprised if this kind of arrangement would be more cost effective than load cells.

With the scale arrangement have you considered using a Perspex top with the capacity to attach to the bottom of the keg with Velcro?

For a keezer set up this would make it simpler to ensure it was placed properly and also to remove rather than having to retrieve form the bottom of the keezer.

Can't wait until this is up and running!

 

[megabyte]

The beam from the IR sensors is pretty narrow, I think they're best pointed at an opaque surface as reflections can confuse it a bit.

With the scale arrangement have you considered using a Perspex top with the capacity to attach to the bottom of the keg with Velcro?

For a keezer set up this would make it simpler to ensure it was placed properly and also to remove rather than having to retrieve form the bottom of the keezer.

Can't wait until this is up and running!

Yes, coincidentally I've been considering this but for different reasons. Your point about convenience has sold me further on the idea.

My reasoning was more about how you explain the concept to people. Explaining to potential customers why they need a bluetooth scale for their kegs is a bit of a hard pitch until you list all the features and benefits because it's just not obvious at first, but if we make the sensing discs attach to the bottom of a keg, all of a sudden we're selling "turn any keg into a smart keg" which is much more intuitive and easy to visualise. I think most people can infer that it's going to link to an app and do awesome stuff.

The "Turn your X into a smart X" concept isn't new, examples include Chronos and Trivoli, turning regular watches into smart watches.

 

[contrarian]

That makes good sense, I'd be happy to help with some infomercial style advertising with kegs blowing at inappropriate times like the middle of a party, just after kick off in state of origin etc.

As I think about it you might need a variety of attachments. Corny kegs have enough flat bottom for Velcro but I have a 23L that's the same diameter but nearly no flat bottom. I'm sure there's be work arounds for any keg.

Will they be waterproof? Normal condensation is one thing but if you have a beer leak you could drown them!

 

[megabyte]

Yeah, I do worry about all the different keg shapes and how they will mate up. I have some from china with odd diameters and metal bases that look like the bottom of a coke can. I am yet to test them all for magnetism (so we could possibly use magnets instead of velcro). Stainless tends to become ferromagnetic after you punch it into different shapes. I'm not sure if the slight dome on the base of a keg is enough to make it ferromagnetic though.

We're going to need a video like what you describe in our kickstarter launch. Origin is a good idea but I don't think we can organise a script and camera crew by Wednesday. I'll have to tape it

I've been thinking about how to make it waterproof and I still don't have an answer yet. It could be designed to tolerate being flooded by 1cm of water or so, but to make it dunk-proof it would need some special design around the load cells (that need to support unrestricted movement) and the battery bay. Any ideas?

 

[contrarian]

For different keg types you wouldn't want more than 2 or 3 different attachments. For anything with a flat surface Velcro would work. Magnets might be ok but not for cornys with rubber bottoms.

For anything with a thinner metal lip some kind of clip, sort of like a bulldog clip but just push on should do the trick, either Velcro or magnets.

Ha! You might run into some small copyright issues using origin but I'm sure the basic idea is sound! Hate running out of beer unexpectedly? You need smart kegs from digital homebrew!

Waterproofing is tricky. The first things that spring to mind are either an arrangement where the bottom of the load cells sit under a sealed case but not sure if that could work or not.

The other thing that popped into my head is a zip lock bag style enclosure for the whole thing. I'm sure there would be something used in kayaking or other water sports that will do the job.. Let me work on that!

 

[peteru]

http://www.maxbotix.com/ looks like a good resource for ideas - even if you don't end up using one of their sensors, they still have some valuable info.

 

[peteru]

I found some awesome (fully sick) sensors here, but I suspect they will all be out of the price range for mounting these in a bunch of kegs.

https://www.sick.com/us/en/product-portfolio/fluid-sensors/level-sensors/c/g98155

 

[peteru]

I've been applying my brain to this problem. Along the way, I investigated some TDR (time domain reflectometry) concepts but came to the conclusion that the high speed electronics required for short distances would make it too hard and expensive.

So far the best candidate seems to be an acoustic solution. It may be possible to come up with a very simple solution, where you have an audio impulse source and a microphone that captures the reflected signal. No need to have it internal to the keg, just use an elastic strap to attach it to the side of the keg. A little bit of signal analysis should give you the time to the various reflections. You would probably need to train your estimation algorithm for each keg type you use.

Given that the keg level can be estimated within normal frequency range that people can hear (just by tapping it), I suspect that any device intended for audio could be used for hacking. In particular, I'm thinking a bluetooth headset - it has both a speaker and microphone and could be butchered/repurposed for some experimentation. Mind you, for the first pass at a proof of concept, you could just use mobile phone held to the side of the keg!

 

[takai]

Looks like you beat me to it. I currently have a prototype setup using Raspberry Pints and a gutted bathroom scale running through an Arduino for communication to the Pints.I figured i would just use Pints rather than rolling anything new as it would just be easier.

Currently i have it jerry rigged to display raw output to a simple Arduino LCD shield, which works relatively well. Have run out of time right now to do more though.

 

[Matty3450]

I havent read the complete post so please ignore if it has been mentioned. A digital flow meter may be an alternative

 

[SBOB]

I havent read the complete post so please ignore if it has been mentioned. A digital flow meter may be an alternative

been covered

 

[megabyte]

Updates!

I was playing with Untappd last night and finally decided to request an API key. If we can integrate with Untappd it makes sense because:
1. I'm a long-time Untappd fan.
2. You'll be able to check-in your beers from the barmaiden app as you pour them rather than launching a separate app.
3. You'll be able to use the Untappd database to easily import beer details when you have a keg of commercial brew on tap.
4. Other cool stuff?

Progress has been a little slow on the hardware front as we've been busy working on our business model. Last week we demoed the Barmaiden concept (along with the rest of our business) to a review panel at our local startup accelerator, so fingers crossed we were able to impress them enough to accept our application. It seemed like they enjoyed the presentation even if they declined to sample the beer from the keg (possibly because it was 9:15am?).

Can't wait to get back to prototyping. We still need to build a "looks-like" prototype and our 3D printer isn't big enough to print it in one go. The alternative is to glue smaller bits together and paint them, but I think it's going to look like a dog's breakfast. Time will tell!

 

[technobabble66]

Ok.
Looks like all youse nerdy nerds are soaking up the tech volume adequately.
I'll focus on the cool name [emoji41]

TapMaiden* (sorry for the ripoff, MB)
iTap, eTap (-names already used)
iPour*, ePour
iBar, eBar (-names already used)
KegDisplay, TapDisplay
TapMenu*, KegMenu, BarMenu*
The Tapperator* (it goes with the Kegerator!!)
The Beer Show

* - personal fav's

I'll keep brainstorming [emoji57]

 

[contrarian]

Just to bump this thread the slogan for this could be 'never blow unexpectedly again!'