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Show HN: Use iPhone's camera as a lux meter

https://www.impulsearc.com/wavelength/

After suffering one too many times from bad jet lag, I read a bunch of circadian rhythm papers and developed a simple app to help fight jet lag. I knew that avoiding devices at night was helpful, but it turns out that getting the right light at specific times of day can help not just with jet lag but overall sleep and well being.How it works: you give the app your sleep goal, and then it...

( Read More... | no comments | 2 points | on HN )
Having just spent a few months reading circadian entrainment papers for a circadian rhythm app I just finished,[1] I wonder if this effect might be about circadian amplitude[2] (rather than phase, which has gotten more attention).

[1] https://www.impulsearc.com/wavelength/

[2] e.g. https://www.nature.com/articles/s41540-023-00300-w

You might find some benefit from an app like Wavekength[1] that uses iPhone camera to coach your light exposure, based on current+desired circadian rhythms.

Disclaimer: I made the app.

[1] https://www.impulsearc.com/wavelength/

Show HN: I Derived a Steak

https://www.absurdlyoptimized.com/recipes/grilled-meats/

After years of juggling imprecise grilling recipes and temperatures, I've made a grilling calculator that derives perfect meat results from thermal models, Fick's law of diffusion, protein structures, and more.Along the way I calculated exactly how far in advance to salt meat (spoiler: even when it's frozen!), realized the best dry brine is usually "cling brine" (covered), derived approximate...

( Read More... | 1 comment | 5 points | on HN )
Re: on Tuesday June 09, 2026 @02:15AM (#48457192)
Thanks a lot!
Re: on Tuesday June 09, 2026 @02:08AM (#48457150)
I made them again this morning and took a new photo that's not overcontrasted from iPhone's built-in photo contrast. I'll get my fancier camera out like a real food blogger next time!
Re: on Tuesday June 09, 2026 @01:40AM (#48456956)
Thanks - I used to have this but decided checkboxes were less useful for properties that don't require dynamic recomputation, so I added this as options. In the writeup I mention that avocado oil contributes no flavor, so it's very predictable but doesn't add flavor (which may be fine!).
Re: on Monday June 08, 2026 @07:30PM (#48453909)
Added!
Re: on Monday June 08, 2026 @05:08AM (#48442950)
Ah, I know about these big tall pancakes! I've had something like that in the Netherlands and grew up eating something like it too.

I'll soon add a fluffiness slider back in so that at the lowest end, it tries to produce something close to crêpes, and you can tell me if it is like the Swedish recipes. Thanks for the international perspective!

Re: on Monday June 08, 2026 @04:30AM (#48442713)
Love it, thanks! I used to have a "fluffiness" slider that I could bring back to power this. I haven't researched Swedish pancakes yet but are they leavened at all?
Re: on Monday June 08, 2026 @02:09AM (#48441824)
Hilarious, thanks for pointing me to that!
Re: on Monday June 08, 2026 @02:07AM (#48441817)
Haha, just for you - check out the new checkbox at the bottom of the form:

https://www.absurdlyoptimized.com/recipes/pancakes/?have=&eg...

I'll leave the rounding of the absurdly precise ingredients to you. :)

Re: on Monday June 08, 2026 @01:59AM (#48441781)
Thanks a lot! Good idea re bread - can you link me to your favorite more general recipes that show all the extremes/variables? I've skimmed some bread textbooks re enriched doughs and have made some Italian breads with sourdough starters, enriched doughs like challah, and once tried the NYT Dutch oven bread, but I don't make bread as often as I make pancakes.
Re: on Monday June 08, 2026 @01:56AM (#48441758)
Thanks! The layout was inspired by the way my mother recopied her recipes. When I first saw how most recipe books wrote recipes, I was so confused! As for baseline ingredients, it's basically (any liquidy dairy) + (everything else in the recipe). I'll think on how to present this better, thanks for the feedback!
Re: on Monday June 08, 2026 @01:53AM (#48441749)
Thanks, I'm working on this next - stay tuned or join the mailing list (will send a very occasional message about new recipes)!
Re: on Monday June 08, 2026 @01:02AM (#48441485)
Haha, already researched the thermometer but haven't pulled the trigger yet! https://www.absurdlyoptimized.com/cooking/ir-thermometer/
Re: on Monday June 08, 2026 @12:27AM (#48441327)
Good to know - I used to have a crispness slider but I removed it since I loved the pancakes at the current crispness. Contrary to the overcontrasted photo, they actually have just a very fine bit of crisp layer. That said, I know that typical American diner pancakes are very soft through, which means people must enjoy them that way too. I can bring back the crispness if other people like their pancakes soft!
Re: on Monday June 08, 2026 @12:20AM (#48441296)
Hahaha, glad you're enjoying it as much as I did! I will have to add a crispness slider and then validate it with expensive audio equipment.
Re: on Sunday June 07, 2026 @11:44PM (#48441101)
I feel your pain - dealt with a lot of those calculations so the calculator could avoid powders!
Re: on Sunday June 07, 2026 @11:06PM (#48440906)
Re: on Sunday June 07, 2026 @10:58PM (#48440858)
Good idea, added! If you have only vegan dairy checked, it'll go for vegan butter too. :)

https://www.absurdlyoptimized.com/recipes/pancakes/?have=soy...

Re: on Sunday June 07, 2026 @10:55PM (#48440846)
Re: on Sunday June 07, 2026 @09:44PM (#48440481)
For sure - if you check "milk" and "lemon" and select maximum tang, you'll get nice tangy pancakes. I opted away from vinegar due to taste but would be curious to hear if someone tests vinegar vs lemon!
Re: on Sunday June 07, 2026 @08:41PM (#48440161)
Thanks! It's entire chunks of fat from a Berkshire pig. Lard works too and is what you get when you render pork fat, but the rendering removes some flavor. I'll update the recipe.
Re: on Sunday June 07, 2026 @03:15PM (#48437695)
After 25 years of making other people's pancake recipes - always yearning for more tang, more fluff, and more predictability - I decided to derive the pancake recipe from the chemistry.

You mark checkboxes for what you have on hand (ricotta, sour cream, kefir, buttermilk, yogurt, cottage cheese, lemon, cream of tartar, etc.) and it computes the best recipe based on targets for acid, fat, salt, sugar, and CO2.

My particular favorite are the yeast-raised lemon ricotta kefir pancakes - the best I've ever had.

I'm not a chemist, so if something is off, tell me and I will fix it!

Re:The Synology End Game on Friday August 29, 2025 @01:51PM (#45067281)
I do video postproduction and am trying to archive/backup 100-250GB of large files per month. Ended up very slowly rsyncing to Synology NAS, confirming checksums with another script, using Synology onboard stuff to backup to AWS, and dealing with all the totally random hard drive noise.

If I want to work on one of these old projects, I have to download it locally so 4K editing works.

Meanwhile my old projects back when I used different software are impossible to open.

I have spent days setting up all this junk, HATE the Synology UI, and regret it all.

What’s the better solution? Just a bunch of RAIDs that I connect to with USB??

Re:Why is zero plural? (2024) on Wednesday January 22, 2025 @07:14AM (#42791922)
“Sans personne” means “without anyone” and has no “ne”.
Re:I Quit the Tsunami of Burnout Few See on Saturday January 11, 2025 @01:04PM (#42667682)
> Burnout isn't well-studied or understood. It didn't even have a name when I first burned out in the 1980s.

Check Wikipedia: “Staff Burnout: Job Stress in the Human Services” was published in 1980, and the Maslach Burnout Inventory was published in 1982.

> We don't bother collecting data on why people quit, or why people burn out, or what conditions eventually break them.

A quick search of academic literature shows this is not true.

Re:Music and Geometry: Intervals and Scales on Friday December 20, 2024 @12:41AM (#42468588)
This is not true.

Singers and violinists can and do adjust intonation so each chord sounds (justly) in tune. The exception is if they were trained with equal tempered instruments (which is common nowadays - see Duffin, “How Equal Temperament Ruined Harmony”) or if they are playing with pre-quantized (fretted/keyed) instruments, in which case they would match the existing temperaments.

So the linked article, while it shows some beautiful shapes linked to 12s, has nothing to do with actually (justly) in tune music.

Source: master’s degree in the topic; am a professional singers specializing in music written before equal temperament was invented

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