My attempt to measure hydrometer displacement

[chris2012]

I've just created a system to measure the displacement of the hydrometer automatically:

https://www.anfractuosity.com/projects/zymeter-simple/

The issue is, at the start of the SG graph, you can see a big bump, which can only be due to the explosion
of yeasty foam in my opinion.

It does seem to roughly match the SG readings I've taken manually, though today.

The experiment is still running, so I'll keep updating the graphs.

I'm hopefully going start on some other approaches soon.

[BenB]

Nice! You'll need a shed load of starsan to soak the float in though Very nice idea though!

[basswulf]

Nice work although I think care needs to be taken over both the effect of the foam and also how much gunk settles on the hydrometer and weighs it down. Since the hydrometer is really nothing more than a floating weight then I wonder if you could replace with a differently shaped weight in the tube - for example, a cylinder at the top for stability and an inverted cone at the bottom to reach through any foam but not collecting any trub as I've observed in the past when trying to monitor a hydrometer left in the fermentor.

Wulf

[chris2012]

Yeah definitely the foam is a big issue.

I'm hopefully going to try working on an ultrasound approach
soon, and taking samples from the middle of the beer, to avoid the foam.

[weetabixface]

How do you intend to use ultrasound? Time of flight or amplitude of successive reflections

W

[chris2012]

Hi, I found a really nice thesis on this. It's a combination of ToF and amplitude.

Have a look at how it should hopefully work on http://hackaday.io/project/1231-zymeter

[weetabixface]

nice summary, remember as a student reading a lot of Papadakis' papers

IIRC couple of other ways of measuring reflection coefficient

W

[Jocky]

Very cool. I look forward to seeing how the ultrasound version works.