Corny Scales

[RoomWithABrew]

This project worth a look at from the maintainer of Brew pi remix, might be a help in your plans.
https://www.homebrewtalk.com/threads/keg-cop-keg-monitoring-and-control.692880/

 

[Regfixit]

I'm planning to have a go at similar using this approach: Pi smart scale Mainly because I have an old Wii balance board gathering dust and having read through it seems no dismantling/wiring etc is needed.
I'd also seen this one: hackster beer scales where they use cheap bathroom scales instead of getting the load cells separetly and building some kind of frame.

Will be interesting to follow how you get on as I have three keg setup and will be great to know when they are getting ready to change - and to track how much my son is pilfering when my back is turned !

 

[BatGlenn]

I'm pretty new to kegging and it took one emptying of my keg to make me want to build something like this so I had a rough idea of how much beer I had left.

I ordered a circle of MDF the same width of my corny keg base, hooked those same load cells up to an ESP32 and a small OLED screen and then had it push the weight value to an IoT dashboard (unidots- same one they recommend to use with the iSpindel hydrometer) every time the keg gets lighter. I 3D printed a case a for all the electronics to tidy it up.

I was thinking of making a website, sharing the code and making it an open source project. This is currently v2, I'm thinking of moving most of the electronics to the base and just having the screen in the 3D printed bit.

Also I messed up the case - the ribbon cable should really be going into the bottom of the electronics case instead of being out to the side, things would be much tidier!

 

[The-Engineer-That-Brews]

I ordered a circle of MDF the same width of my corny keg base, hooked those same load cells up to an ESP32 and a small OLED screen and then had it push the weight value to an IoT dashboard (unidots- same one they recommend to use with the iSpindel hydrometer) every time the keg gets lighter. I 3D printed a case a for all the electronics to tidy it up.

I was thinking of making a website, sharing the code and making it an open source project. This is currently v2, I'm thinking of moving most of the electronics to the base and just having the screen in the 3D printed bit.

Excellent job that's pretty much exactly what I had in mind - and the same sensors too. Did you have any problems with creep?

 

[BatGlenn]

Thanks! I've had a look at some of the other projects linked in this thread and it's amazing how much overlap there is for the same solution.

In terms of creep, honestly I don't know yet - I'm still experimenting with it. It's mostly been hooked up to a power bank rather than plugged in, so I haven't had it on long term to see creep materialise on my dashboard yet. I'm not too worried about it, so long as I can get a very rough idea oh how much is left in my keg I'm happy enough :)

 

[The-Engineer-That-Brews]

Toys have arrived :-)

Somewhat relieved to find that the load cells themselves are a bit more substantial than the ones in the listing image ...

 

[Joust]

Toys have arrived :-)

Somewhat relieved to find that the load cells themselves are a bit more substantial than the ones in the listing image ...

View attachment 49612

Let us know how long it took for you to say a terrible swearword and threaten to take a sledgehammer to it

 

[The-Engineer-That-Brews]

Let us know how long it took for you to say a terrible swearword and threaten to take a sledgehammer to it

hopefully that won't be necessary

 

[crowcrow]

How is it going?

 

[The-Engineer-That-Brews]

How is it going?

Still in the project queue ;-) I’m currently writing ESP32 Bluetooth drivers for my diy tilt hydrometer. I do know about the iSpindle but I’m using this as an opportunity to learn more about BLE/NimBLE

 

[Duffmann]

I'm pretty new to kegging and it took one emptying of my keg to make me want to build something like this so I had a rough idea of how much beer I had left.

I ordered a circle of MDF the same width of my corny keg base, hooked those same load cells up to an ESP32 and a small OLED screen and then had it push the weight value to an IoT dashboard (unidots- same one they recommend to use with the iSpindel hydrometer) every time the keg gets lighter. I 3D printed a case a for all the electronics to tidy it up.

I was thinking of making a website, sharing the code and making it an open source project. This is currently v2, I'm thinking of moving most of the electronics to the base and just having the screen in the 3D printed bit.

Also I messed up the case - the ribbon cable should really be going into the bottom of the electronics case instead of being out to the side, things would be much tidier!

Did the same just with a raspberry pi sitting in my keezer handling all three kegs and constantly updating via WiFi and mqtt to my home mqtt broker with nodeRed.

Works like a charm and the pi has still open ports for more.

 

[eyuptm]

"Keg ball" has to be the simplest low tech solution.

Is that the magnetic balls and floating magnets in the corny? I've seen it somewhere, seems to be the simplest, least expensive solution...

 

[foxbat]

Is that the magnetic balls and floating magnets in the corny? I've seen it somewhere, seems to be the simplest, least expensive solution...

Yes that's the one. My own method is to try and remember to note down how many pints have been pulled in my beersmith records. The accuracy of this method is... err... prone to error...

 

[crowcrow]

Is that the magnetic balls and floating magnets in the corny? I've seen it somewhere, seems to be the simplest, least expensive solution...

I like that idea, but my kegs don't have a lot of room around them as I stick loads of bottles and sometimes food in the keezer.

Back to the topic this popped up for me on YouTube this morning - love this guy!

 

[The-Engineer-That-Brews]

"Keg ball" has to be the simplest low tech solution.

That's genius!

 

[The-Engineer-That-Brews]

Back to the topic this popped up for me on YouTube this morning - love this guy!

Love that - what a dude: "here is de guy wiz de Swiss accent".
If that had been my cat it would have ignored the food and attacked the circuitry.

 

[Benfleet Brewery]

I do love a gadget so I’d love to install something like this at some point. In the meantime, I’ll just stick with my method of leaving the kegerator door open for about 30 seconds and waiting for the line to appear

 

[The-Engineer-That-Brews]

I do love a gadget so I’d love to install something like this at some point. In the meantime, I’ll just stick with my method of leaving the kegerator door open for about 30 seconds and waiting for the line to appear

View attachment 52487

Yes - it's a great indicator that isn't it
I do tend to keep my bitters at close to ambient though...

 

[The-Engineer-That-Brews]

This project has been on the back burner so it's time for an update :-)
In fact after my experiments with the digital hydrometer I very nearly abandoned this project.

The problem is creep, i.e. the tendency for load cell measurements to drift gradually when subjected to a continuous load. This makes it very hard to monitor accurately the weight of a load that is left in place on the scales for long periods of time.

In the hydrometer I fixed this problem by using a servo to lift off the weight between readings. But with a 25kg Corny that would be decidedly inconvenient.

Fortunately I think I may see a simpler solution. My thoughts go something like this:

• The effect of creep should look pretty different to that of drawing off a pint.
• Creep probably looks like a very slow weight increase - maybe of the order of 1 gram per minute.
• In contrast, pouring some beer should look like a much more rapid weight decrease of 50-100 grams per sec.
• So by disregarding any slow weight changes I should be able to track accurately the amount of beer drawn off each time and the running total.
• This leaves the question of the initial volume. However in this case creep is not an issue because the load cells are initially unloaded.

Next step is to do a little testing to establish whether these assumptions are true.

 

[Joust]

This project has been on the back burner so it's time for an update :-)
In fact after my experiments with the digital hydrometer I very nearly abandoned this project.

The problem is creep, i.e. the tendency for load cell measurements to drift gradually when subjected to a continuous load. This makes it very hard to monitor accurately the weight of a load that is left in place on the scales for long periods of time.

In the hydrometer I fixed this problem by using a servo to lift off the weight between readings. But with a 25kg Corny that would be decidedly inconvenient.

Fortunately I think I may see a simpler solution. My thoughts go something like this:

• The effect of creep should look pretty different to that of drawing off a pint.
• Creep probably looks like a very slow weight increase - maybe of the order of 1 gram per minute.
• In contrast, pouring some beer should look like a much more rapid weight decrease of 50-100 grams per sec.
• So by disregarding any slow weight changes I should be able to track accurately the amount of beer drawn off each time and the running total.
• This leaves the question of the initial volume. However in this case creep is not an issue because the load cells are initially unloaded.

Next step is to do a little testing to establish whether these assumptions are true.

https://www.ebay.co.uk/itm/Hall-Eff...p2349624.m46890.l6249&mkrid=710-127635-2958-0
This was my next step after finding the hx711 hard work