8 ms·
A CD Spectrometer (2006)
- tecleandor 3y agoOh, 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. It's a fun thing to do in an afternoon. 0: https://publiclab.org/wiki/papercraft-spectrometer
- wcrossbow 3y agoAt 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.
- diracs_stache 3y agoCan you give a hint without doxxing yourself?
- wcrossbow 3y agoI work for Kuva Space P.S. Doxxing me is trivial based on what is already available in this forum
- diracs_stache 3y agoNice, hyperspectral imagery has some very interesting applications. Cheers!
- isoprophlex 3y agoAnd here I was, thinking this was about circular dichroism! Cool article nonetheless..!
- higginsc 3y agosame! I was excited to see something so esoteric from my grad school days come up
- anfractuosity 3y agoI recently got a spectrometer with a fibre input from fleabay, which I've been enjoying playing with. I got a tiny ruby stone and shone a tungsten halogen light behind it - https://www.anfractuosity.com/files/ruby.png 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_transmittance.svg 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 https://shop.wf-education.com/science/op66595.html. And simply attached to a camera, to generate graph from.
- HerculePoirot 3y agoA $500 DIY near-IR spectrometer that would sell for $10,000 https://caoyuan.scripts.mit.edu/ir_spec.html https://caoyuan.scripts.mit.edu/ir_spec.html
- anfractuosity 3y agoLooks very impressive!, thanks
- qwertox 3y agoCurrent discussion: https://news.ycombinator.com/item?id=37498142 https://news.ycombinator.com/item?id=37498142
- OJFord 3y agoWhat 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.
- anfractuosity 3y ago
- msk-lywenn 3y agoDoes using a DVD or Bluray instead of a CD improves the result? The angle might have to be different?
- symmetricsaurus 3y agoIn 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!
- SamBam 3y agoWhat's the pitch between tracks?
- anfractuosity 3y agoThat 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 https://www.anfractuosity.com/files/cd-r.JPG
- dylan604 3y agowhat 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
- anfractuosity 3y agoIt's an Olympus BHM that I got cheaply from ebay. It's a trinocular metallurgical microscope, that I added an old SLR to, for that photo. I noticed the semi-silvered mirror seems rather scratch though, so might need to look at replacing that.
- userbinator 3y agoHere's a video showing the construction of one based on the same principle, but using a camera for wavelength measurement: https://www.youtube.com/watch?v=p3MzQ1OF3lk https://www.youtube.com/watch?v=p3MzQ1OF3lk
- lasermike026 3y agoOh my word, that's awesome!
- 1-6 3y agoI'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?
- jonhohle 3y agoI’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.
- TacticalCoder 3y agoHow does that work? Are you using a CD to tell if one fluorescent bulb is better than another? Or to tell if one bulb is LED or incandescent or ...? > 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!
- crazygringo 3y agoUsing 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.
- 1-6 3y agojust hold the CD at an angle to the light source and stare at the reflective surface
- peter_d_sherman 3y agoAbsolutely and utterly brilliant! 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!
- dang 3y agoRelated: Constructing a spectrometer using a CD - https://news.ycombinator.com/item?id=10285117 https://news.ycombinator.com/item?id=10285117 - Sept 2015 (9 comments)