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Ask HN: What's the coolest physical thing you've made?

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Re: Ask HN: What's the coolest physical thing you've made?

#601
post #597
post #591

Earlier quoted context omitted.

I own 4.2 acres in the Sierras north of US-50 between Kyburz and South Lake Tahoe at 5,600ft elevation. It was not easy to find, but there is a seasonal creek that runs through it fed by snowmelt. I had to drill a well 600ft down to find water year round, there are no utilities so I had to dig out for septic, get propane storage for generator power, and I have a gravel path via an easement into an adjacent property t…

It would be interesting to figure out scientifically why places like the one you mentioned cause this kind of effect on the human brain.

I only have anecdata, but I have identified two factors: isolation and vulnerability, or rather the sudden change in how isolated or vulnerable we feel. We become accustomed to the sounds of our own neighborhood and city in general, so if you stop all these sounds and introduce new ones, in addition to literally being isolated and unable to read others’ emotions on the situation, our brains generate discomfort via anxiety and stress. The vulnerability aspect is due to the fact that we don’t know what’s out there. When we’re walking around in the darkness, our brains are determining that we are in danger and attempts to signal to us that we need to GTFO. Being in terrifying situations will heighten that response.

Re: Ask HN: What's the coolest physical thing you've made?

#603
post #593

I made a rotary input device that provides software-defined "virtual" detents and end-stops, implemented using a BLDC gimbal motor. It can dynamically switch from completely smooth unbounded rotation, to having detents with configurable spacing and strength and "end-stops" that spring back if you try to rotate past them. https://www.youtube.com/watch?v=ip641WmY4pA It's got a round LCD on the front of the knob (wired…

that video of yours just popped up on my YT feed yesterday! did it get "YT-algoed"?

Hah, yeah I think it may have. I've noticed an increase in comments over the last few days, which usually suggests the algo is showing it to new people again, and it got featured on the Adafruit blog this morning which probably reinforced it further, but no idea why the recent resurgence.

Re: Ask HN: What's the coolest physical thing you've made?

#604
post #91

I made a person seven years ago. They started out pretty useless, just eating and pooping and crying a lot. But now they can walk, talk, think, read, write, act, sing, and love.

My wife also says this, but I’m fond of pointing out that she didn’t create our children, they created themselves!

Right, you just provided seed capital.

Re: Ask HN: What's the coolest physical thing you've made?

#606
post #321

Earlier quoted context omitted.

They're in two gists here: https://gist.github.com/kaspermeerts/781f0137b361b51224dcab7... https://gist.github.com/kaspermeerts/b6f158b1278de307e48a200... I just hacked it together, but I do think it's not unreadable code

> but I do think it's not unreadable code hopefully your boolean conditionals are easier to read than that

Is. Not. Not. = Is.

Re: Ask HN: What's the coolest physical thing you've made?

#607

I made a baseball bat that uses explosives to add a bunch of energy to your swing and hit a baseball really far. It uses the explosive blanks normally used to shoot nails into concrete (e.g. ramset). It worked way better than I expected, didn't have a kick, and turned out to be just a really neat thing to look at while sipping a frosty beverage. I also made a video about it if you're interested: https://youtu.be/Puo6…

Your productivity absolutely phenomenal. Each video that comes out seems like you make what would take a normal person a good part of a year to produce in a fraction of the time.

Re: Ask HN: What's the coolest physical thing you've made?

#608

Earlier quoted context omitted.

I'm not sure I'd be able to figure it out easily if I didn't already know how a CAT scan works, but I agree it's a excellent demonstration of the principle

Not knowing how a CAT scan works, beyond a vague intuition from already knowing what the acronym stands for, and not wanting to look it up before making a guess: can I assume it’s akin to this, in that radiation is shot from an emission source, through the target, to a detector on the other side, with the density of the material attenuating the signal in predictable ways, from which we can apply a transformation to s…

indeed.

In a closer analogy to a CAT scan, each nail would have a string connecting it to a ~10 degree spread of nails on the opposite side, and each string would be grayscale.

The real physics is quite tricky, because you actually emit a variety of x-ray energies at once, each with different penetrating power, and xray flux varies spatially as well. this means each of your angular strings has its own grayscale response curve.

heres a simple rundown: https://radiologykey.com/computed-tomography-16/

Re: Ask HN: What's the coolest physical thing you've made?

#609

I made a clock based on an IV-18 vacuum florescent display tube. In the process I learned CAD, CNC, aluminum anodizing, metal turning, SMT soldering, laser cutting, box making, power supply design, and a dozen other skills I use every day today. Here's the clock's homepage, which has some pictures: https://vonnieda.org/tc18 , and more pictures on Flickr: https://www.flickr.com/photos/vonnieda/sets/7215762293577593...…

The eBay listing is dead, so I have to ask… what did it sell for?!

Re: Ask HN: What's the coolest physical thing you've made?

#610

My telescope(s). It's a very rewarding hobby, from making the mirror (manual labor + measurements with interferometry), silvering it (a bit of chemistry), designing in CAD and building the actual usable telescope, there are a lot of moving parts to design, and steps that you can either do or delegate. I think anyone who likes manual work can find a piece of a telescope that's enjoyable to work on. The feeling you get…

So amazing. Do you have an astrobin.com? Mine is here: https://www.astrobin.com/users/bhouston/

Really nice work ! I don't, as I'm doing 100% visual. Your Sadr region picture is really beautiful with subtle contrasts preserved
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