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carpdiemon Show HN: Ember – Redshift safe color palettes

How's this for an example webpage?

https://www.usuallypragmatic.com/ember/

It has live examples in coding / data visualization / image display / animation / etc, with the ability to toggle the color palettes as well as toggle redshift on/off.

carpdiemon Show HN: Ember – Redshift safe color palettes

Fair point on the naming collision. I know these sorts of color filters end up with different names via different apps on different platforms, so just describing it as 'redshift safe' seemed like the lesser evil.

And it's an great question about relativistic redshift! That actually would end up with more or less the opposite result: you'd want to shift all of your palette colors and meaning into commanded-blue channels.

That's because the relativistic redshift pulls everything to longer wavelengths, so as you approached the speed of light, you'd start literally losing colors as they got red-shifted out of the human visual range.

The first thing you'd lose is the red channels (which would get shifted into the infrared, and thus be invisible). That happens at about 0.2c, depending on the wavelength of the red LEDs in your screen.

Then you lose green once you get to about 0.38c.

Blue doesn't disappear from your visible range until you get up to ~0.52c.

Faster than that, and the only things you'll be able to see with naked eye started off as ultraviolet frequencies (or above)! (aka - you'd need HW changes to your screen, so it's outside the realm of SW to fix)

carpdiemon Show HN: Ember – Redshift safe color palettes

That's a... surprisingly deep question. I'm actually a physicist by background first, so I got my start doing waaayyy too many calculations with blackbody and emissions spectra.

Then, back in 2010, when I was just getting into startups, I spent two weeks straight at Powell's in Portland reading through their graphic design section.

After that, I never got very far away from light or perception... AR/VR -> graphics -> silicon photonics -> physical AI (now).

I'm still very much learning, but if you like this stuff and want to learn more yourself there's a couple sources I can recommend:

- Interaction of Color, by Josef Albers. Amazing book, but you really want to get a physical copy.

- I really like this talk from SciPy 2015 to get a sense of how people work with and talk about color maps in practice: https://www.youtube.com/watch?v=xAoljeRJ3lU

- This is a really, really thorough (and beautifully illustrated) article on what color spaces are: https://www.makingsoftware.com/chapters/color-spaces-models-...

- And last, I wrote a very technical blog post a few years back, if you want to see some math on a bunch of this: https://www.usuallypragmatic.com/projects/Generating-Color-T...

carpdiemon Show HN: Ember – Redshift safe color palettes

Added in a Table of Contents at the top to improve it for now. May do more substantial re-writes later.

carpdiemon Show HN: Ember – Redshift safe color palettes

Really glad you liked it! I use an absurd amount of redshift personally, and have spent too much time thinking about / working on light-and-color related projects, so it came out of a place of need and love alike.

carpdiemon Show HN: Ember – Redshift safe color palettes

Can I ask which parts? I wrote the intro section by hand, and left the rest of it Fable-generated with significant "guidance" and rounds of re-writing.

I think the current weakest part is the explanation of the science behind it, but I'm curious if there was anything specific that jumped out at you.

carpdiemon Show HN: Ember – Redshift safe color palettes

Example web pages is a great idea. It's a very new project (just did it over a couple of evenings during a trip last week), so there's nothing formal out there yet, but I'll add in some contrived examples later today.

carpdiemon Galaxy XR: The first Android XR headset

It's interesting that there are essentially no pictures of the actual device anywhere on this page (except for a lone image, from the back of a user's head, where all you can see is the strap and the edge of the front).

carpdiemon Project Hyperion: Interstellar ship design competition

Another ISSDC alum here, but from a little more than a decade earlier. It really was a unique experience. I remember the finals at Kennedy Space Center fully exercised the extent of your mental and physical stamina both. It also delivered lots of surprisingly applicable lessons for startup life around coordinating technical teams in high-stress, high-stakes environments.

carpdiemon Interstellar Flight: Perspectives and Patience

1 AU is about 8.3 light minutes. So 6k AU is about 50k light minutes. with ~525k minutes in a year, that means that 6k AU/yr is almost exactly 0.1c.

carpdiemon The future of solar doesn't track the sun

I used to work on solar power plants and solar tracking technology back in the late 2000s. Even back then, I remember frequently discussing that "eventually panels will be cheap enough that we'll just wallpaper the world...". It's really nice to see that coming true.

carpdiemon Go and my realization about what I'll call the 'Promises' pattern

Lordy, I clicked on this, fully expecting a discussion of a shape-pattern in the board game of Go, and somehow didn't have a thought in my mind for the real, completely different, meaning.

This reminds me of "trompe l'oeil foods"... dishes that appear to be one thing, but are another entirely. Or maybe optical illusions more generally.

carpdiemon AppleWatchAmmeter

I tried this once. There was no convincing effect for being able to "detect by feel" AC currents, but you could definitely notice magnetic materials.

Maybe the most fun, though, was just playing around and "picking up" paperclips and tiny screws by flicking my finger at them.

carpdiemon Ask HN: What are some "toy" projects you used to learn neural networks hands-on?

https://www.mnist.org

I wanted to actually build first-hand intuition on all of the choices around hyperparameter choices, activation functions, network architectures, etc. So I've been rigorously exploring them by training and testing models off of the mnist dataset.

Coming up soon: vision transformers, depth-of-architecture on CNNs, batch size investigations, and more.

Let me know if any of you have any suggestions of things to investigate next!

carpdiemon Miyazaki Might Be Right: Cases of a Town, a City, a Province, & a Country

I'm all for innovative ideas in supporting families and children, but the examples from the article hardly count as "successfully reversing fertility declines".

- Nagi, Japan. TFR: 2.95 (replacement rate is ~2.1). Astonishing. This is the only true success in the article.

- Nagareyama, Japan. TFR: 1.5. At this rate, the population will drop by ~25% every generation.

- South Tyrol, Italy. TFR: 1.64. Marginally better than Nagareyama. Noticeably better than the rest of Italy (TFR: 1.2), but still a population in strong decline.

- Czechia. TFR: 1.6 (https://data.worldbank.org/indicator/SP.DYN.TFRT.IN?location...). Better than the European median, but not exceptional. Roughly on a par with Lithuania (1.63), Belgium (1.59), and the UK (1.57). Noticeably behind France (1.79). None of these countries at such TFRs are even capable of maintaining their population at a stable level, and should all be regarded as undergoing some level of population collapse.

carpdiemon I organized a 20-acre game of Capture the Flag

That sounds crazy, and amazing. As I've now got a kid of my own who might eventually be interested, could you point out _which_ intensive wilderness school in Washington that is? I did some googling, but wasn't able to find it.

carpdiemon Instinctive Sleeping and Resting Postures (2000)

It would be interesting to know how the comfort or suitability of these postures is affected by physiology.

For example, even the suitability to obtain a deep squat may be affected by things like hip joint geometry: https://www.otpbooks.com/stuart-mcgill-hip-anatomy/

carpdiemon The Life and Death of the Bulbdial Clock

I'm reasonably good friends with Windell & Lenore, and I think "gobbled up" is not the right way to look at it.

It's my understanding that they've known the folks at Bantam for some time now, and that given how hard it can be to run a physical product company (especially one that does some in-house manufacturing for your own products!) in the bay area, that they're looking forward to having such niceties as 'pto'.

They're really excellent people, and made a huge difference to me when I first moved to the bay area, so while it's sad to see them leave, I understand it, and hope this leads to a better situation all around for them.

carpdiemon Relativistic Spaceship

Doesn't really work this way. A lot of the wonkiness in SR is tied to the fact that the speed of light is the same, measured in _any_ reference frame.

So, say you're on earth and you measure the speed of light... you find that it's c (~3x10^8 m/s).

Now you get on a spaceship and accelerate to 0.5c with respect to earth, and you measure the speed of light relative to your spaceship... still c!

In this way, you can't really define a reference frame with a speed "the same as the speed of light". And if you try, you'll run into nasty infinities in all your equations that will cause them to blow up and stop being useful.

carpdiemon Ask HN: Small scripts, hacks and automations you're proud of?

Most useful script I've ever written, and legitimately how I keep track of everything important in my life:

  #! /bin/bash

  function todo {
   if [ $# -eq 0 ]
    then
     vim ~/Dropbox/todo/todo_list.txt
    else
     vim "$HOME/Dropbox/todo/todo_list_$1.txt"
   fi
  }

Sourcing this in my shell means I just have to type...

  todo

To automatically get into my default todo list which is synced to dropbox (and thus accessible everywhere on mobile as well).

While, whenever I have a new project/etc come up, I can just

  todo new_project_name

And get a new, nice clean file, with the same backups and multi-device accessibility.

carpdiemon Physics and Mathematics Self-Study Project

One more vote from me for mathacademy.com!

For reference, though I now work in tech, I have a physics degree from a top-10 worldwide university, and reviewing linear algebra on math academy has not only been great to re-learn things I've forgotten, I'm confident that it's taught me at least a few things that I've never encountered before.

So yeah, it's legit in my book.

I also think that one of the reasons it gets such rave reviews/etc from folks using it is that it's, frankly, not that well known yet, and we users who like it _really_ like it, so we want to see it stick around and grow further for our own use too!

carpdiemon Ask HN: What RSS Reader do you use in 2022?

One more vote for feedly from me! One of the few online subscriptions I don't mind at all paying for. I especially like the ability to auto-generate email addresses for newsletters to "turn them into" RSS feeds within feedly.

carpdiemon How to rebuild social media on top of RSS

At the risk of sounding like a shill, have you tried Feedly? (feedly.com)

I switched over to it ages ago after the death of google reader, and it's held up remarkably well for me, and now also includes welcome features for, e.g., intaking email newsletters, conducting automatic content-specific web searches, etc into the same RSS-reader UI.

It's one SW subscription I'm happy to pay for.

carpdiemon Ask HN: Can you recommend me a book to (re)learn math?

Ignore all the other answers and skip straight to this one. Math Academy is amazing. It's got everything you could want (mastery based learning, knowledge graph dependencies, assessment tests, a hint of gamification to encourage you to learn more, even spaced repetition reviews) and its coverage and depth of the material is _excellent_.

For specific example, I've literally studied linear algebra probably close to a dozen times in my life, including full courses from two different universities whose names end with "institute of technology", and I'm currently using math academy to review the subject again. I've already encountered several things that are straight up new to me, and the presentation/practice and spaced repetition review of the things I just never managed to lock into my long term memory is already helping me finally own them.

carpdiemon California starts sending out stimulus checks up to $1,050

When I first heard about this, I thought "oh man, how dumb! they're just going to make inflation worse!", and then I read more of the details.

By my understanding, the case for stimulus checks leading to inflation comes when the stimulus checks are paid for by printing more money (thus increasing the overall money supply).

This program is not that. This program is providing a tax refund from CA's tax surplus. No new money is being created. The only change is who gets to decide how the money is being spent? (e.g., the state? or the people?)

If CA could have seen the future, they could have achieved the same end by lowering taxes this last year for people in an equivalent amount. Would anyone seriously argue that lowering taxes is inflationary? How about the contrapositive? Would anyone seriously argue that we should fight inflation by _raising taxes_?

carpdiemon How a razor blade can be damaged as it cuts human hair (2020)

Could you clarify a little more about what you mean by this? Tomato skins are definitely hard to cut with a dull knife (without crushing the tomato flesh underneath), so many people will default to using a serrated knife for them, hoping that the scalloped edge grabs and tears the skin.

That said, a well sharpened kitchen knife should have no problem at all with tomato skins.

carpdiemon How a razor blade can be damaged as it cuts human hair (2020)

These ideas are mistaken.

"Sharpness" is related to the physical size and radius of curvature of the apex of the blade, combined with the angle of the terminal bevel. [1][2][3]

Chipping of any sort almost certainly tends to erode the sharpness for many reasons, not least of which is that a sharp edge is a very low entropy state (compared to a dulled / chipped / etc edge...).

VG-10 steel is considered "entry level" in terms of high end steels. [4] It was first introduced in production knives in the mid-90s, almost thirty years ago! [5] And there has been significant progress in materials since then.

Almost all mid- and high-end knives these days are cut from blanks via an industrial laser or waterjet cutter.

-----

[1] https://scienceofsharp.com/2014/01/25/quantifying-sharp/

[2] https://scienceofsharp.com/2014/08/18/definitions-of-sharp-a...

[3] https://scienceofsharp.com/2015/03/24/sharp-and-keen-part-2/

[4] https://www.bladehq.com/cat--Best-Knife-Steel-Guide--3368

[5] https://forum.spyderco.com/viewtopic.php?t=87185

carpdiemon Electrical engineers on the brink of extinction threaten entire tech ecosystems

Can you share more details about how that hiring process tested for that? I'd love to hear about it.

carpdiemon Ask HN: Share your personal site

All right, I'll bite:

https://www.usuallypragmatic.com

I'm a physicist who's landed in the tech industry, so it's full of all sorts of miscellanea.

Here's a few good places to start:

https://www.usuallypragmatic.com/misc/Logarithmic-Birthdays....

https://www.usuallypragmatic.com/projects/Generating-Color-T...

https://www.usuallypragmatic.com/blog/2020-08-10-How-do-you-...

https://www.usuallypragmatic.com/projects/How-do-you-learn-(...

carpdiemon PG&E will bury 10k miles of power lines so they don't spark wildfires

Not really. Trees are actually somewhat hard to burn, so most wildfires start by catching dry underbrush on fire instead. So in this case, that would just be the alfalfa.

Key to remember is that power lines can spark when they're damaged by winds (which can lead to the lines themselves being close enough to the ground for the spark to traverse to the underbrush).