http://www.raspberrypi.org/archives/3841 (http://www.raspberrypi.org/archives/3841) got me thinking....If you had some way of measuring the weight of the keg you'd know how much you'd left.
While the weight of the keg would work best, you can get flow meters for a lot cheaper. Just start with ~19L and the flow meter will subtract from that regardless of glass size. I have to say that the interface on the application in your link is amazing.
I'd love a setup like that!
My programmer mate mentioned a Raspberry pi and flow meter when he saw my finished keggerator. Nerds are great.
This may be more like it:
https://kegbot.org/
Now, where's my soldering iron...
That kegbot is deadly!
Quote from: imark on May 03, 2013, 06:33:27 PM
http://www.raspberrypi.org/archives/3841 (http://www.raspberrypi.org/archives/3841) got me thinking....If you had some way of measuring the weight of the keg you'd know how much you'd left.
I started work on a keg weighing device a good while ago.
Needless to say i never finished it. I documented my progress in a thread on beoir as far as i remember.
Also, needless to say, it got shelved when i got bored and had higher priorities :)
It was basically a hacked electronic scales hooked up to an AVR processor (same chip used in an arduino)
(Insomnia cure alert!!)
Here's what i did. Took the scales apart to reveal a strain gauge arranged in a wheatstone bridge. Basically applying weight to the strain gauge causes the resistance to change meaning you get a very small voltage change that you can measure with your microcontroller. Since its so small you need to amplify the signal using an op amp.
I was reading it in and cant remember whether i had successfully converted the output from above to digital using the AVR - this task would be alot easier using arduino and its built in framework vs using the bare chip as i was doing. (Think of it as all-grain vs a kit)
So basically its the price of a cheap electronic scales (aside from the microprocessor) and a suitable op-amp. ~15 euro.
Flow meter is a neater solution. Weight of the beer depends on gravity - the weight of the keg when its empty would need to be taken account too and this could change for diff kegs. With a flow meter there is nothing like that to worry about other than knowing the amount you started with in the 1st place - so that you know you're getting near the end.
Flowmeters from .nl are not cheap tho' $60 + $20 postage!!
Get a flowmeter on aliexpress for about $12. Had a look around the other day and couldn't find anything else close.
http://m.aliexpress.com/item/808817606.html