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.
Ask HN: What's the coolest physical thing you've made?
601–610 of 694 posts
Re: Ask HN: What's the coolest physical thing you've made?
#602Was really happy with the design, considering I just made it up on the spot. I had previously carved a few chess sets before though out of wood.
Re: Ask HN: What's the coolest physical thing you've made?
#603I 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"?
Re: Ask HN: What's the coolest physical thing you've made?
#604I 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!
Re: Ask HN: What's the coolest physical thing you've made?
#605[1] https://en.m.wikipedia.org/wiki/FIRST_Robotics_Competition
Re: Ask HN: What's the coolest physical thing you've made?
#606Earlier 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
Re: Ask HN: What's the coolest physical thing you've made?
#607I 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…
Re: Ask HN: What's the coolest physical thing you've made?
#608Earlier 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…
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?
#609I 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...…
Re: Ask HN: What's the coolest physical thing you've made?
#610My 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/