What an excellent write-up. Very clearly explained, and the use of gifs and visuals to illustrate concepts was spot-on. I'm only a software engineer with a limited understanding of this field, but really enjoyed reading this and learned a lot. Well done and congrats on the PhD.
Show HN: I made a new sensor out of 3D printer filament for my PhD
131–138 of 138 posts
Re: Show HN: I made a new sensor out of 3D printer filament for my PhD
#132This is really neat—thanks for sharing! I love the general idea of making materials more "self-aware" or inspectable. It's very sci fi! The research I did before my current job touched ever so slightly on this too, so even cooler to see it on the front page. What we were doing was using complex valued neural nets to learn the transmission matrix of an optical fibre. It was previously done in the optics community by p…
could it detect a twist instead of a bend?
Maybe with polarization maintaining fiber? If at the gap they are aligned a teist will make them more perpendicular reducing mode coupling.
Disclaimer: I know nothing about this field but have spent a lot of time in a dark lab surrounded by various types of optical fiber.
Re: Show HN: I made a new sensor out of 3D printer filament for my PhD
#133What an excellent write-up. Very clearly explained, and the use of gifs and visuals to illustrate concepts was spot-on. I'm only a software engineer with a limited understanding of this field, but really enjoyed reading this and learned a lot. Well done and congrats on the PhD.
Thank you!
Re: Show HN: I made a new sensor out of 3D printer filament for my PhD
#134As sometime about to start a PhD in theoretical physics, how did you do 3 years? I've been told a doctorate is 2 years of classes followed by 3 to 5 years of research. Did you already have a masters that you're doctorate college accepted to override class requirements?
The short answer? Weekly meetings with my advisor! Long answer: I also had 2 years of classes but I started working on my research immediately, while taking classes. By the time I finished all my classes and became a candidate I had one paper already published and another one accepted, so I was able to get a 3rd paper out and defend by the end of the 3rd year.
With all do respect, I think you're telling a half-truth here. Your LinkedIn profile shows you had two MS degrees before starting your PhD. Undoubtedly you got some of the requirements waived for the PhD course requirements. That means your total time post BS was 5 years. I did the same thing - 1.5 years (3 semesters) MS and then came back later (different school) to do a PhD and got half the course requirements waived. Finished the PhD in 4 years but total time post BS was a more humble 5.5.
Re: Show HN: I made a new sensor out of 3D printer filament for my PhD
#135This has inspired about a hundred ideas in my head. Thank you!
(They're all ways which on paper seem like I might be able to do things better, but if the sort where 95% don't pan out in practice. Everything from machine learning algorithms to identify shapes to fancy encoding with spectra of what reflects along the path to other ways to engineer changes in the path)
Re: Show HN: I made a new sensor out of 3D printer filament for my PhD
#136Have you explored fiber bragg grating. 10 years ago a student of mine semi successfully explored sensing the shape of firefighter hose using that technique. Seems to gain new traction again lately for optical shape sensing.
The perpetual issue with FBGs is cost, in my experience. For quality sensors, you can use cheap fibre with expensive detectors, or cheap detectors with expensive fibre. There's been a perpetual promise of the tech getting cheaper, but never seems to really drop significantly. We always struggled to find buyers once they saw the price tag.
Reading about them, the main reason is because you have to manufacture regularly repeating slices of glass in a column over large distances whose thicknesses are usually on the order of the wavelength you're dealing with. So visible light requires some really small slices.
I could probably make fiber bragg gratings in my ceramics studio, yet it would require buying some Very specific thickness glass sheet, setting up a bunch of hole punch jigs to get 1 m worth out of 1 um slices, figuring out some way to actually layer 1,000,000 slices correctly, and then not just melting them to slag accidentally.
Re: Show HN: I made a new sensor out of 3D printer filament for my PhD
#137Earlier quoted context omitted.
The perpetual issue with FBGs is cost, in my experience. For quality sensors, you can use cheap fibre with expensive detectors, or cheap detectors with expensive fibre. There's been a perpetual promise of the tech getting cheaper, but never seems to really drop significantly. We always struggled to find buyers once they saw the price tag.
Reading about them, the main reason is because you have to manufacture regularly repeating slices of glass in a column over large distances whose thicknesses are usually on the order of the wavelength you're dealing with. So visible light requires some really small slices. I could probably make fiber bragg gratings in my ceramics studio, yet it would require buying some Very specific thickness glass sheet, setting up…
The ones we purchased were made in two different ways. Production ones were made by using a diffraction pattern of UV light to modify the refractive index of the core slightly, the other was using femptosecond lasers to alter it more dramatically.
The UV light method worked fine, came out to about $600US per fibre with 32 gratings each, not exactly cheap. The measurement unit was on the order of $20k US though.
Re: Show HN: I made a new sensor out of 3D printer filament for my PhD
#138Earlier quoted context omitted.
Reading about them, the main reason is because you have to manufacture regularly repeating slices of glass in a column over large distances whose thicknesses are usually on the order of the wavelength you're dealing with. So visible light requires some really small slices. I could probably make fiber bragg gratings in my ceramics studio, yet it would require buying some Very specific thickness glass sheet, setting up…
The ones we purchased were made in two different ways. Production ones were made by using a diffraction pattern of UV light to modify the refractive index of the core slightly, the other was using femptosecond lasers to alter it more dramatically. The UV light method worked fine, came out to about $600US per fibre with 32 gratings each, not exactly cheap. The measurement unit was on the order of $20k US though.
That kind of surprises me, since then I'd figure that somebody would be making the equivalent of a reprap that puts out glass filament like this 3D glass printer [1] or various glass resin methods ([2] and [3]) Just with some kind of inline laser processing, or post deposition modification. Most of those use UV or lasers anyways. The methods mentioned don't seem like those should cost $20,000/unit unless the unit's 1km+.
[2] https://ethz.ch/en/news-and-events/eth-news/news/2019/11/gla...
[3] https://www.glassomer.com/products/glass-3d-printing.html