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Ask HN: What rabbit hole(s) did you dive into recently?

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Re: Ask HN: What rabbit hole(s) did you dive into recently?

#241

Post by jancsika »

perihelions wrote: post #208
eddd-ddde wrote: post #191

Earlier quoted context omitted.

Question since you are probably knowledge-able about it right now. > Another observation: lots of people create PDF's at print-quality pixel density that's useless for screens, and greatly increases rendering latency. Is this relevant to text in the PDF? I would assume text is vectorized, meaning resolution is not relevant until you _actually_ print it? Or is it just relevant to rasterized content like embedded image…

Your understanding's right: PDF's that are text + fonts are easy and fast. I'm concerned about the other kind, that's scanned pages. Any sheet music from Petrucci / imslp.org for one example. That kind is a sequence of raster images, stored in compressed-image formats which most people aren't familiar with, because they're specialized to bi-level (1-bit, black and white) images. A separate class from photo-type image…

> A separate class from photo-type images.

I'd assume that the photo-type image decoder is optimized, right? If so, how does the optimized photo-type decoder compare to the apparently unoptimizable JBIG2 decoder?

Re: Ask HN: What rabbit hole(s) did you dive into recently?

#242

Post by mianos »

brcmthrowaway wrote: post #184
peteforde wrote: post #135

I did not realize that learning Fusion 360 was going to be such a huge chapter in my current journey. Looking back, I'm kind of stumped at how I avoided it as long as I did. I would now put learning CAD in the same category of mandatory life skill as learning to code. The ability to translate what you see in your mind to something that can be repeatably fabricated is an incredible power move, akin to learning how to…

Do NOT use this proprietary nonsense, learn FreeCAD

I am a developer, FreeCAD is a bit of fun to wrangle a model out as a puzzle but it's not even in the same universe as Fusion360.

I'd love to use something like KiCAD is in the EDA world.

I highly expect, at any moment, Audodesk to pull the rug from under the hobbyist licence and I'll not be able to use it anymore.

While I feel kinda 'dirty' when I use it, I have been using it for maybe 8 years and the thing is a masterpiece. It's like a third arm for me.

Once your brain knows the whole constraints workflow it is so natural. I can very quickly model up pretty much anything I can think of to make.

Re: Ask HN: What rabbit hole(s) did you dive into recently?

#243

Post by nyjah »

JamesSwift wrote: post #222
nyjah wrote: post #176

Golf simulation. I found myself in a unique situation where I had the space, computer and projector. So I got a mat, screen and the key piece, a launch monitor. Now I’m playing 9-36 holes of golf simulation almost every day. The tech is great, the setup is never ending. Golf simulation tech is blowing up right now too. I’m not even necessarily a golfer fwiw. But I love the simulator.

I'll never set it up but I'd love to hear about the tech choices/options.

The software that I am using to simulate the courses is GSPro. There are hundreds of courses on there. It's got just about every course you could imagine.

Launch monitors come with their own software too and there are a few other options for simulating courses. E6 is one and GolfClub2019 is another. AwesomeGolf. GSPro is hard to beat though.

For launch monitors, there are two main types: camera based and radar.

Garmin offers the most affordable radar based option with R10 for around $600.

Bushnell offers an all camera model and for $2000 you get all the ball data. For a subscription fee you can play GSPro and other 3rd party golf apps using the Bushnell and for another fee you can get all the club data. This model sits beside the ball.

FlightScope has a launch monitor that operates with radar and/or camera and sits behind the player. For about $1800 you can get the ball data and its free to connect it to GSPro. For another $1200 you can get club data, with impact location. It's unreal how accurate this thing is. I've had mine for about a year, and since then they have pushed some incredible updates, including what they call "Fusion", which is combining the camera and radar for readings. Its how their really expensive 20k+ unit works.

At the very top end there are monitors that go on the ceiling and give you readings from there. And then there are commercial simulators where the floor will move up and down. It really never ends. One company showcased lighting from above that shows you where you should putt. It never ends. . .

https://gsprogolf.com/

https://www.garmin.com/en-US/p/695391

https://www.bushnellgolf.com/products/launch-monitors/launch...

https://flightscope.com/

https://www.foresightsports.com/pages/gchawk

https://uneekor.com/

Re: Ask HN: What rabbit hole(s) did you dive into recently?

#244

Post by whoopsie »

Bluetooth coffee mugs. I disliked Ember’s app, particularly on Mac, so I built a substitute for the menu bar. While expanding to knockoff mugs on Amazon, it was entertaining to see how bizarre and inefficient some BLE implementations were. Some write every second unnecessarily. Ember starts the heater during cooldown, even though they could do so closer to target temp and save 5-10% battery.

Re: Ask HN: What rabbit hole(s) did you dive into recently?

#245

Post by kromem »

therealcamino wrote: post #190
kromem wrote: post #30

I started looking into the Gospel of Thomas right before the start of the pandemic, which led to a number of rabbit holes: * Turns out the work is not 'weird' or 'Gnostic' but is directly addressing details from Lucretius, including paraphrasing his view of evolution and atomism, but refuting the claim there's no afterlife by basically appealing to the idea we're in a simulated copy of an original physical world wher…

Is that the one where Jesus sells Thomas into slavery because he didn't go obediently to minister to the people in India?

No, that's the mythology that develops around the travels of an apostle Thomas much later on.

I'm pretty sure that there was no 'Thomas.' My guess is that the philosophy of being in a twin universe and a twin of an original humanity ends up anthropomorphized by or before "doubting Thomas" in John and ends up credited with the tradition making those philosophical claims which was also denying the physical resurrection.

In the Gospel of Thomas itself, there's only two mentions of a 'Thomas,' both likely later additions. Moreso the work features him having female disciples and discussions directly with them, and the only later tradition following it claimed a female teacher named Mary as the starting point of their sect.

The Gospel of Thomas is a collection of sayings, and that core may have gone by different names before the 2nd century when it's rolled up in a more secretive context as attributed to 'Thomas' (despite the core itself seemingly being more anti-secretive than any other texts in the early Christian tradition).

Re: Ask HN: What rabbit hole(s) did you dive into recently?

#246

Post by mianos »

So many great rabbit holes in this list. There are several that have blown years of my spare time.

My one, at the moment is precision time keeping. Time nuts. I have a pile of oven controlled crystal oscillators, GPSs (even the full Ublox time specific LEA M8).

I got a BG7TBL counter and multiple cheap GPSDOs to test my own.

I have a DAC1220 20 bit DAC on an ESP32 disciplining a TCXO from an old phone base station by counting the 10Mhz using the PCNT and gated off the GPS 1PPS.

Meantime, I learnt the esp-idf so I could have more control over things. Everything done with the esp-idf is way way more stable than using the Arduino wrapper, no idea why, maybe later versions?

The disciplining/tracking parameters are exposed by http and mqtt and put into influx.

I have a 5.5 digit multiple meter (I repaired the classic HP 3478A). Maybe I need another digit, there goes another rabbit hole. Voltnuts.

Re: Ask HN: What rabbit hole(s) did you dive into recently?

#247

Post by bigiain »

bambax wrote: post #149

Was into cine drones for a while; then discovered FPV. Spent dozens of hours on simulators, now flying actual FPV drones in manual mode. Incredibly addictive. I'm having a hard time focusing on anything else right now.

Heh. I was building/programming/racing FPV drones in 2013/14, back before teenaged reflexes and rich dads paying thousands for top line gear became a thing - and easily started beating 50 year old eyesight and reflexes with self imposed budgets of only a few hundred bucks...

Re: Ask HN: What rabbit hole(s) did you dive into recently?

#249

Post by perihelions »

jancsika wrote: post #241
perihelions wrote: post #208

Earlier quoted context omitted.

Your understanding's right: PDF's that are text + fonts are easy and fast. I'm concerned about the other kind, that's scanned pages. Any sheet music from Petrucci / imslp.org for one example. That kind is a sequence of raster images, stored in compressed-image formats which most people aren't familiar with, because they're specialized to bi-level (1-bit, black and white) images. A separate class from photo-type image…

> A separate class from photo-type images. I'd assume that the photo-type image decoder is optimized, right? If so, how does the optimized photo-type decoder compare to the apparently unoptimizable JBIG2 decoder?

I'm not knowledgeable to speak to that, but just to clarify—the low-hanging fruit in libpng I mentioned is in simple, vectorizable loops—conversions between pixel formats in buffers. Not in its compression algorithm (which isn't part of libpng—it calls out to zlib for that).
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