I'm planning on using it to try to measure ABV of beer/spirits. I noticed some of the cuvette holders with fibre inputs seem to be crazy expensive though, so probably need to DIY that!
What sort of wavelength of sensor do you need for ABV measurements? Size of ethanol particle? Half it because of Nyquist? Or what does it have to relate to?
I'm just wondering how fancy vs. DIY you need for that sort of purpose basically.
This is the paper I've been looking at - https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3356901/ they make use of a tungsten lamp and IR leds, I tried with just a tungsten lamp and only really saw a plateau around 900nm when ethanol was present. Their spectrometer goes further into IR than mine, mine tops out around 1000nm, but hopefully I'll still be able to get some results when I add IR LEDs.
I'm not sure what the peaks correspond to regarding the ethanol molecule though afraid. It's been a while since I read the paper, but maybe that indicates this.
I believe my spectrometer just has a linear CCD sensor.
For ABV you'd usually use refractive index, there are low cost non-electronic refractometers, you can also use density. Alcohol doesn't absorb much light so generally not done by UV or IR.
Oh, for a while Public Lab's Paper Spectrometer [0] was very popular in "citizen science" workshops or forums. It was made peeling the diffraction grating of a DVD-R (not a +R) disc.
At my current company we build satellites with imaging spectrometers as payload and wanted to propose building a bunch of this on our upcoming team day. I was hoping for the non-technical team to get a better feeling of what is that we are trying to sell.
In my high school physics class we measured the pitch between the tracks of a CD using the same principle. You just need a light source with a known wavelength, like a laser. It was a pretty cool experiment!
That sounds a fun project :) I tried a little peeling of a CD-R under a microscope, where can see the tracks, I should try and measure the pixel distance and convert to track width - https://www.anfractuosity.com/files/cd-r.JPG
what microscope are you using? i've been itching to get into microscope photography for a new hobby, but because i know myself, it'll be a fun but expensive rabbit hole. i've been deliberately putting off on researching because i also know myself and will be just as likely to be shopping than researching
This is an awesome picture! Forgive me if this is a stupid question but are we seeing 0s and 1s here? Is that what the black is? Kind of the equivalent to a morse code dit (0) and dah (1)?
I would have never in a million years thought of this use for a plain old CD... but yes, after reading this article, yes, I now see how a CD Spectrometer could indeed work!
I've been checking the quality of my light sources for years using a CD (florescent vs LED vs incandescent). Didn't DIY'ers know this technique for years?
I’ve been wanting to check my lights and didn’t know about this.
A few years ago we had several cans replaced with solid state LED fixtures and my wife has had a lot of trouble with sleep which roughly correlates. It may be placebo, but it seems like she also may get better sleep when watching an OLED TV vs an LCD iPad. It made me wonder if we should put 460nm filters on our ceiling lights.
Using a 0.2 mm slit? Or do you have an easier way that uses just the CD?
First I've ever heard of it, and I went pretty deep into the rabbit hole of spectrum when I switched to LEDs in my home. Don't think this is very common knowledge.
Readit News
I got a tiny ruby stone and shone a tungsten halogen light behind it - https://www.anfractuosity.com/files/ruby.png I could see a dip around 694nm like someone else's spectrum - https://en.wikipedia.org/wiki/Ruby_laser#/media/File:Ruby_tr.... This is the same wavelength that ruby lasers emit light apparently.
I'm planning on using it to try to measure ABV of beer/spirits. I noticed some of the cuvette holders with fibre inputs seem to be crazy expensive though, so probably need to DIY that!
A while ago I got a little spectroscope that looked a bit like - https://shop.wf-education.com/science/op66595.html. And simply attached to a camera, to generate graph from.
https://caoyuan.scripts.mit.edu/ir_spec.html
It should move from ~1.15eV at room temp 75F/25C to ~1.10eV at 120F/50C, which should be about 35nm longer.
I'm just wondering how fancy vs. DIY you need for that sort of purpose basically.
I'm not sure what the peaks correspond to regarding the ethanol molecule though afraid. It's been a while since I read the paper, but maybe that indicates this.
I believe my spectrometer just has a linear CCD sensor.
It's a fun thing to do in an afternoon.
P.S. Doxxing me is trivial based on what is already available in this forum
I would have never in a million years thought of this use for a plain old CD... but yes, after reading this article, yes, I now see how a CD Spectrometer could indeed work!
Again, absolutely and utterly brilliant!
Upvoted and favorited!
A few years ago we had several cans replaced with solid state LED fixtures and my wife has had a lot of trouble with sleep which roughly correlates. It may be placebo, but it seems like she also may get better sleep when watching an OLED TV vs an LCD iPad. It made me wonder if we should put 460nm filters on our ceiling lights.
> Didn't DIY'ers know this technique for years?
I used to live in a rural area (fixing everything in the house by myself) so I'm quite the DIYer but I don't know anything about that!
First I've ever heard of it, and I went pretty deep into the rabbit hole of spectrum when I switched to LEDs in my home. Don't think this is very common knowledge.
Cool article nonetheless..!
Constructing a spectrometer using a CD - https://news.ycombinator.com/item?id=10285117 - Sept 2015 (9 comments)