Help with Brixometer design  - Page 1
Forum section: electronics / projects

author: kaperdomo
author_rank: Newbie
timestamp: June 09, 2019, 07:15:24 pm
content: I have to make a brixometer/refractometer. This is a device used to measure the amount of sugar in a liquid. That's achieved by shining a ray of light through a piece of glass, and the light is refracted differently when the liquid has different levels of sugar in it.The part I need help with is coming up with a circuit that will turn that refraction into an electrical signal and then showing it as the percentage of sugar in the liquid. So far, all I have is an LDR and an Arduino, but I realized I also need an LCD to display the number, and I'm not sure how to connect it, I would like to see if someone could help me with that. Also, if someone can come up with a better way, please let me know.Enviado desde mi MRD-LX3 mediante Tapatalk

author: strawberry
author_rank: Super Contributor
timestamp: June 09, 2019, 09:14:18 pm
content: Your circuit will have low resolution. I guess sugar in a liquid wont give much change in voltage for ADC

author: jbb
author_rank: Super Contributor
timestamp: June 09, 2019, 10:48:10 pm
content: An LDR might be the wrong tool for the job:- I think a lot of them use Cadmium Sulphide (CdS) in the sensor. Cadmium is toxic and should be avoided- you’ll only get a measurement at one point. Don’t refractometers offer a sort of bar output?Maybe a linear photodiode array (or disassembled webcam) would be better?

author: jct
author_rank: Contributor
timestamp: June 10, 2019, 08:03:52 am
content: Look at the following electronic hydrometers for a more accurate solution:https://tilthydrometer.comand even some opensource:https://github.com/universam1/iSpindel

author: soldar
author_rank: Super Contributor
timestamp: June 11, 2019, 08:17:37 am
content: Quote from: kaperdomo on June 09, 2019, 07:15:24 pmThat circuit is a total non-starter. You are way over your head here.Brix is more commonly measured by measuring specific gravity. Note that temperature also needs to be taken into account.What range and what precision do you need?Degrees Brix to Specific Gravity Conversion Tableshttp://www.cobell.co.uk/uploads/downloads/SG%20Tables.pdf

author: CJay
author_rank: Super Contributor
timestamp: June 11, 2019, 10:13:48 am
content: Never heard of a Brixometer before but the idea intrigued me and I immediately thought of a linear CCD array from a scanner or fax machine, turns out optical Brix meters are pretty cheap and they already exist with digital readout, using CCD arrays to measure the change in refractive index caused by a sample on a prism.Neat application of technology and there's plenty of info about using CCD arrays with an Arduino too so from a brief read, I think the most difficult bit could be sorting out the optics.You're almost definitely wasting your time with a CDS cell.

author: cur8xgo
author_rank: Regular Contributor
timestamp: June 11, 2019, 06:32:37 pm
content: Quote from: soldar on June 11, 2019, 08:17:37 amThis."The part I need help with is coming up with a circuit that will turn that refraction into an electrical signal and then showing it as the percentage of sugar in the liquid. " represents the entire project, doesn't it?Step 1, which cannot and should not be skipped, is a strategy here for how you will accomplish the project, _as project manager_ before you even get to the engineering.

author: kaperdomo
author_rank: Newbie
timestamp: June 11, 2019, 06:43:12 pm
content: Quote from: soldar on June 11, 2019, 08:17:37 amI need just enough precision to measure sugar in water, not other liquids. And the range would not be that big, considering it's just for measuring that.Enviado desde mi MRD-LX3 mediante Tapatalk

author: soldar
author_rank: Super Contributor
timestamp: June 11, 2019, 09:10:55 pm
content: Quote from: kaperdomo on June 11, 2019, 06:43:12 pmThat does not answer anything and hardly makes sense. If you want to get help at least you need to communicate what you want clearly.Quote from: kaperdomo on June 11, 2019, 06:43:12 pmWhat? Qué?