Could you get a similar effect by cutting dimples or notches in patterns (like a helical line of small conical holes) along the whole length in a sleeve instead of using separate pieces and infer overall curve shape? Or do the segments need to be cut completely through?
Show HN: I made a new sensor out of 3D printer filament for my PhD
101–110 of 138 posts
Re: Show HN: I made a new sensor out of 3D printer filament for my PhD
#102I've been looking for a sensor that can accurately detect a golf club sweeping over the top of it (how close, how quickly, arc of swing). The idea being to create a golf launch monitor that doesn't require hitting a ball, so you can play sim golf inside. Think playing alongside the Masters as you watch on TV in the lounge - without smashing a golf ball through your TV. I am wondering if this could be suitable (or a n…
Seems like a hall sensor or two plus a magnetic club head is what you need
Re: Show HN: I made a new sensor out of 3D printer filament for my PhD
#103I don't understand what happens when the sensor is bent in more than one location.
At the beginning you mention a ToF sensor, which made me think that you're looking at reflections from the bends and measuring distance to them, but this seems not to be the case. ISTM that if you bend the sensor in two places, you'll simply get the sum of the logattenuations from both. If we assume that the "strength" of the bend continuously changes attenuation, ISTM that you need as many strands as there are gap locations to be able to disambiguate between any two sets of bends.
Am I misreading something or is this intended to operate in cases where we know only one bend is present?
Re: Show HN: I made a new sensor out of 3D printer filament for my PhD
#104[dead]
Re: Show HN: I made a new sensor out of 3D printer filament for my PhD
#105Isn't this just the same tech as the first Nintendo Power Glove had? https://www.youtube.com/watch?v=3g8JiGjRQNE
They put light down a tube and then measured the light to trigger a key press. That's why bending your fingers/hand did anything. The revised the mechanism in the later generations.
Re: Show HN: I made a new sensor out of 3D printer filament for my PhD
#106I've been looking for a sensor that can accurately detect a golf club sweeping over the top of it (how close, how quickly, arc of swing). The idea being to create a golf launch monitor that doesn't require hitting a ball, so you can play sim golf inside. Think playing alongside the Masters as you watch on TV in the lounge - without smashing a golf ball through your TV. I am wondering if this could be suitable (or a n…
Seems like a hall sensor or two plus a magnetic club head is what you need
Some kind of electromagnetic sensor does seem like a way to go. Not sure of the practicalities of magnetising/ keeping magnetised a golf club head though.
And ideally it would work with all of your clubs or at least all your metal clubs, not just one special club.
Re: Show HN: I made a new sensor out of 3D printer filament for my PhD
#107This 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 propagating Maxwell's equations, but we were able to beat the state of the art by a few orders of magnitude with a very simple architecture (the actual physics just boils down to a single complex matrix multiplication!). The connection to your work here is that if the fibre is bent you have to relearn a new matrix. It could even be possible to learn some parameterized characterisation of the fibre, so you could say do some input/output measurements and use that to model a spline of the fibre. We did not get that far though!
Here are the papers if you're interested:
CS-focussed one: https://papers.nips.cc/paper_files/paper/2018/hash/148510031...
Physics-focussed one: https://www.nature.com/articles/s41467-019-10057-8
Re: Show HN: I made a new sensor out of 3D printer filament for my PhD
#108Very beautiful research and thorough documentation. I initially wanted to comment that this looks a lot like time-domain reflectometry on a conceptual level - but as Cindy Harnett seems to be your advisor, you probably know that already :)
I did some work on TDR analysis when analyzing CATV fraud detection but it turns out that we generally know where on the fiber plant each CPE is and collecting the DOCS IS timing data from those devices is essentially free.
Re: Show HN: I made a new sensor out of 3D printer filament for my PhD
#109Very cool to see how it all came together. Can you elaborate on why you chose to use a Kalman filter in your signal chain?
I used it more for future-proofing in case I wanted to do sensor fusion or something like that later on -- currently it's just 1D filtering so I could have used anything. Also I'm just way more familiar with using Kalman filters so it was also a comfort thing!
Re: Show HN: I made a new sensor out of 3D printer filament for my PhD
#110As 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.
Wow