Kegbot (flow meter and digital taplist) project

[mr_wibble]

Could you please give us a few notes on how you performed the calibration ?

 

[Moad]

She does not know the URL, if she does find it...I will change it.



Calibration I used water to get each meter ball park measurements using a 500ml flask. I then hooked up the beer and poured ~250-350 mls into a schooner and weighed it vs an empty schooner.

I assumed 1g = 1ml which is probably wrong but the measurements I am getting from kegbot seem pretty good to me. Around 415-430 for a full schooner with a small amount of head. Slightly over estimating is good for me

I then adjusted the tick/ml and poured again. I will keep testing as I pour for a little while, until I am happy it is reliable and consistent

 

[dblunn]

What about when SWMBO has a higher score than you :blink:

Jeez, I never considered that ever happening.

I assumed 1g = 1ml which is probably wrong but the measurements I am getting from kegbot seem pretty good to me. Around 415-430 for a full schooner with a small amount of head. Slightly over estimating is good for me

Use the FG, so if it were 1.010 then 1 ml would be 1.01 g . That is only 1% so not worth worrying about.

 

[contrarian]

How are you measuring the starting volume? I guess if it's a full keg it isn't too hard but measuring partially filled kegs could be a bit tricky. Apologies if this has been answered in a previous post.

 

[Moad]

Rough guess for existing kegs, I could weigh them to be accurate.

The whole thing is a bit of fun and to roughly know when I'm going to kick a keg so not trying to be accurate to the ml

 

[cspencer]

Rough guess for existing kegs, I could weigh them to be accurate.

The whole thing is a bit of fun and to roughly know when I'm going to kick a keg so not trying to be accurate to the ml

I weighed my kegs while empty and stuck a sticker with the weight on the keg. when hooking up a new keg, weigh it and deduct the kegs weight and put that into Kegbot as the starting volume.

I've stopped recording the drink lately as my system is a manual glass weighing mod after each pour, worked well and now interested in using these flow meters, thanks for the feedback. The Swissflow meters @ $60US each make it an expensive option

if your interested http://kegbot.spencertribe.com:8000

Had a few parties using it and the manual weighting gets way out towards the end of the night, lots of missed pours or double pours recorded.

 

[Moad]

I got a double pour last night, have you done any troubleshooting on that?

 

[cspencer]

I got a double pour last night, have you done any troubleshooting on that?

To be honest I thought it was a User (drunk User) problem as my system is a user tap on the screen when they have the glass on the scales.
So never looked further into it. It's possible the System is posted the same data twice to the server.

 

[Moad]

I've only seen it once in 100 pours, it was an identical pour. Could have been no acknowledgment from the server to the core.

Anyway even with this and one or two pours registering way off I am loving the system. I've dialed all my taps to within 10ml on a schooner now, the test will be if the flow rate needs tweaking on a new keg. I'm wondering if the viscosity of the beer affects the measurements. I'll be tapping a dark IPA after a helles so that should be a decent test

 

[cspencer]

Moad, good to see it's working well so far. Which connectors did you use to connect the flow meter too your beer lines? I'd like to use a 8mm quick connector thing but can't see them on the kegking site

 

[Moad]

cheers mate, they are just 3 pin connectors and 5 pin sockets from Jaycar. They fit together and you just use 3 of the 5 pins on the sockets, just in case you weren't sure!

https://www.jaycar.com.au/3-pin-din-line-plug/p/PP0302

and

https://www.jaycar.com.au/5-pin-din-panel-socket/p/PS0348

I'm sure there are better options but these work for me and were available on the day

 

[cspencer]

Jaycar don't sell them any more, I got mine from AliExpress. They sell on eBay as well if you just want one or two.

http://m.ebay.com.au/itm/1-30L-min-1-75MPa-1-2-quot-Hall-Effect-Flowmeter-Control-Water-Flow-Sensor-Arduino-/201693323507?txnId=1509142147010

Moad Sorry I meant the connecting to the Beer line, i've got 8mm (I think) beerline and the flowmeter you linked early looks to be a 1/2" thread (which sort NPT etc I'm not sure)

 

[Moad]

ahhhh!

I use 5mm line (remember its ID not OD) so needed a small barb.

https://www.aliexpress.com/item/2Pcs-6mm-Hose-Barb-Tail-To-1-2-Inch-BSP-Female-Thread-Connector-Joint-Pipe-Fitting/32685171357.html?spm=2114.13010608.0.0.iNrh7s

Doesn't affect flow rate or foaming etc.

Cheers

 

[stuartf]

Hey moad, really interested in getting something like this set up on my kegerator. How difficult for a non-IT person to build? Also I was thinking of adding in pressure sensors so I can confirm what pressure each keg is at, not sure how easy that would be to do though?

 

[malt junkie]

Hey moad, really interested in getting something like this set up on my kegerator. How difficult for a non-IT person to build? Also I was thinking of adding in pressure sensors so I can confirm what pressure each keg is at, not sure how easy that would be to do though?

Each flow sensor requires an interrupt circuit, each pressure sensor also requires an interrupt circuit, so an arduino could only handle I think 6 taps with flowmeters or 6 pressure sensors or three with both.

 

[Moad]

Not sure about pressure sensors but malt junkie is right, using the arduino mega you can have a max of 6 taps. The back end will read multiple boards, you just have to assign them serial numbers.

Non IT savvy you could work it out with some help (which I am happy to offer). The hardest part is the server side which took some effort for me with minimal linux knowledge. Where are you located?

Something I have noticed after tapping a new keg tonight and I think I mentioned this earlier about pressure being consistent... Because of the minimal headspace in a new keg the pressure drops off quickly when you pour which alters the flow rate. This has affected the measurement of flow for the first few schooners. Once you are ~2L into the keg it isn't an issue but something to be aware of.

 

[Moad]

My system has been really great and consistently within 1L.

over the course of the keg I tweak the flow tick rate a little but not a big issue.

I’ve rebuilt the back end a few times so have a pretty good handle on it now. Got some nfc tokens and swipe on the tablet to automatically assign the pour.

Strongly recommend doing this for anyone with a kegging system and a mild interest in electronics. Happy to assist, the kegbot forum is pretty much dead but I’ve been trying to contribute.

 

[Dubzie]

Thanks for bumping this post.
Recently built a kegerator that will hold 6 kegs and wanted to get some sort of measurement system so i know when I have to put a new brew down.
Considering the flow meters are only $4.60 on ebay it's going to be quite a cheap project to get setup.

 

[meathead]

Thanks for bumping this post.
Recently built a kegerator that will hold 6 kegs and wanted to get some sort of measurement system so i know when I have to put a new brew down.
Considering the flow meters are only $4.60 on ebay it's going to be quite a cheap project to get setup.

Do you have a link to these?

 

[DTrain123]

I just noticed this thread. I was wondering if maybe using load cells connected to an Arduino to measure the weight of the keg would be more accurate/easier to use than the flow rate sensors? It would require building little individual weighing platforms for each of the kegs to sit on.

There's an article here that gives a rough guide on how to interface an Arduino with a load cell: https://www.hackster.io/MOHAN_CHANDALURU/hx711-load-cell-amplifier-interface-with-arduino-fa47f3

The load cell accuracy wouldn't be affected by the CO2 pressure and pour rate. There also wouldn't be any need to weigh the keg before hand or to guess how much the starting volume of beer is. As long as it knows the empty weight of a keg, it could calculate how many kilograms of beer you have remaining at any given time.

Although now that you've already got the flow sensor system working, it's probably a bit late to go changing it now.