HNHacker News
TopNewBestAskShowJobs

montecarl

1,734 karma · joined September 11, 2011

submissionscomments
montecarl··on Ask HN: What are you working on? (May 2026)
I had a raspberry pi 3a+ and the old raspberry pi touchscreen laying around. So I'm writing a custom dashboard for it using Rust/Slint[1]. It directly uses opengl without any display manager/window system. It mostly talks to home assistant. Right now, when I start a 3d print, it automatically switches to a view with live camera of the printer and some stats. I can monitor the status of my washer/dryer so I know when they are done (using cheap TP-Link Tapo smart plugs[2]). My favorite thing it does, is if any motion is detected on my Ring cameras, it just automatically pulls up that live feed. Took a little work to get decent playback performance but the pi 3a+ has hardware h264 decoding.

Its nice, overall, to have a little dedicated touchscreen on my desk that I can easily tweak to display whatever I want. Its silent and low power.

[1] https://slint.dev/

[2] https://a.co/d/044MIM3t

montecarl··on Valve releases Steam Controller CAD files under Creative Commons license
They also did this for the original steam controller, which I used a lot. When the back panel broke (its a trigger and battery cover) I was able to 3d print a replacement that has held up great.

https://steamcommunity.com/games/353370/announcements/detail...

montecarl··on My audio interface has SSH enabled by default
I get it! Thank you that is genius.
montecarl··on My audio interface has SSH enabled by default
I really want to know how he solved this problem, which I also face:

>last year i bought a Rodecaster Duo to solve some audio woes to allow myself and my girlfriend to have microphones to our respective computers when gaming together and talking on discord in the same room without any echo

montecarl··on Show HN: Differentiable Quantum Chemistry
When I read this, I thought that the author would be calculating the derivative of the potential energy with respect to nuclear charge for some reason. Here, the derivative being evaluated appears to be the atomic forces, using jax magic, as opposed to the standard Hellmann-Feynman theorem approach.

Calculating the derivative of the energy with respect to nuclear charge would be fun, as it would let you perform some type of "alchemy" smoothly changing from one element to another. I'm not sure that has any practical use.

I read a paper a while back doing something alchemical that I guess this reminded me of: https://pubs.aip.org/aip/jcp/article-abstract/133/8/084104/1...

montecarl··on Near mid-air collision at LAX between American Airlines and ITA [video]
I think that the audio we are listening too is from some ground recording station that isn't necessarily near the airport. We aren't listening to a recording of what the pilots heard or what air traffic control hears.
montecarl··on AWS to bare metal two years later: Answering your questions about leaving AWS
I can't believe how affordable Hetzner is. I just rented a bare metal 48 core AMD EPYC 9454P with 256 GB of ram and two 2 TB NVME ssds for $200/month (or $0.37 per hour). Its hard to directly compare with AWS, but I think its about 10x cheaper.
montecarl··on AI cheats: Why you didn't notice your teammate was cheating
I play fortnite and marvel rivals with my family. We have lots of fun. I think this genre of game is fantastic if you play with people you know on voice comms. "Solo queuing" in these types of games is not fun for me at all, so I get what you are saying, but they are popular for a reason!
montecarl··on We were wrong about GPUs
Just currently exploring how custom AI workflows (e.g. text to sql, custom report generation using private data) can help given the current SOTA. Looking to develop tooling over the next 3-6 months. I'd like to see what we can come up with before dropping $50-100k on hardware.
montecarl··on We were wrong about GPUs
Do you think that you can use those machines for confidential workflows for enterprise use? I'm currently struggling to balance running inference workloads on expensive AWS instances where I can trust that data remains private vs using more inexpensive platforms.
montecarl··on The young, inexperienced engineers aiding DOGE
Just in case anyone else reads this and is confused. MRIs only use radio waves. No ionizing (or visible or even IR) radiation is used. The strong magnetic fields are a risk (due to interacting with metallic items embedded in the body). The contrast agents also can cause some undesirable side effects.
montecarl··on A generative model for inorganic materials design
I agree that DFT is an approximate solution to the Schrodinger equation, but what would you like to see them do? Quantum monte carlo or configuration integration? These methods do not scale well especially when heavy elements are involved. DFT is the current sweet spot for accuracy vs computational complexity in this field. Making DFT better has been an on-going effort for the 30-40 years at least. It is not an easy task. For many real world materials, DFT is the best we can do.
montecarl··on Tell HN: Impassable Cloudflare challenges are ruining my browsing experience
I'm in a similar boat. A UK bank thinks I'm one of their customers (someone with a similar name). The reply address is no-reply@ and I'm not about to call a foreign bank.
montecarl··on Autodesk deletes old forum posts suddenly
I use fusion 360 several times a week, but I'm not quite able to follow what you said. Can you provide an example or a link to where they announced this feature?
montecarl··on Buildroot
I would love to know. I currently have an embedded product using buildroot and as it is not exposed to a network at all, I don't have any worries about security. However, I'd love to hear of a nice mechanism to basically upgrade the system image in place. I imagine you could use something like a pair of partitions and just change the kernel boot parameters to point at the most recent one, but I'm curious about what solutions people use.
montecarl··on Raspberry Pi Pico does line rate 100M Ethernet
Why is the transfer rate non-linear with respect to the system clock? At 100 MHz the rate is 1.38 Mbit/s and at 200 Mhz it is 65.4 Mbit/s.
montecarl··on Turing's topological proof that every written alphabet is finite (2010)
It is even easier to just say, given a fixed area of paper, and a finite printing resolution, there is a finite number of symbols possible?

Say you have a 1 in by 1 in area of paper and a printing resolution of 300 DPI then there are 300*300 total dots. If the printer is monochrome and each dot is either black or white then there are 2^(300^2) possible symbols.

montecarl··on A rudimentary simulation of the three-body problem
Thermostats ensure that the average _kinetic energy_ remains constant (on average or instantaneously depending on how they are implemented). Your parent post wants to enforce the constraint that the total energy remains constant. So its a bit different from a canonical ensemble (NVT) simulation. This is a microcanonical ensemble simulation (NVE). This means you don't know if you should correct the position (controlling the potential energy) or the velocities (controlling the kinetic energy).

Basically, there will be error in the positions and velocities due to the integrator used and you don't know how to patch it up. You have 1 constraint; the total energy should be constant. There are 2(3N-6) degrees of freedom for the positions and velocities (if more than 2 bodies). The extra constraint doesn't help much!

Edit: Also, the only reason thermostats work is because the assumption is that the system is in equilibrium with a heat bath (i.e. bunch of atoms at constant temperature). So there is an entire distribution of velocities that is statistically valid and as long as the velocities of the atoms in the system reflect that, you will on average model the kinetics of the system properly (e.g. things like reaction rates will be right). In gravitational problems there is no heat bath.

montecarl··on Show HN: Timelock.dev – Send a secret into the future using timelock encryption
What you just wrote reminds me of the song Secrets From the Future by MC Frontalot.

> You can’t hide secrets from the future with math

> You can try, but I bet that in the future they laugh

> At the half-assed schemes and algorithms amassed

> To enforce cryptographs in the past

montecarl··on Show HN: Elodin – A better framework for physics simulation
> there are comments for every line.

I used to work at a company that wrote an atomic scale simulation package. Every dev was a physics/chemistry PhD turned coder. We didn't quite hit one comment for _every_ line of code, but we were close! At first I really hated this style; one comment every few lines. However, I eventually learned to kind of like it, even though it was a bit redundant.

I don't really have a point here, but I just wanted to echo your statement that the physicists-turned-coder style is real!

montecarl··on Claude 3 model family
I really wanted to read the questions, but they make it hard because they don't want the plaintext to be visible on the internet. Below is a link toa python script I wrote, that downloads the password protected zip and creates a decently formatted html document with all the questions and answers. Should only require python3. Pipe the output to a file of your choice.

https://pastebin.com/REV5ezhv

montecarl··on Damn Small Linux 2024
Yes, this brings back such memories for me too! I also used to boot from removable media to use linux on school computers. The librarian assumed I was some kind of computer hacker and reported me to the schools IT admin. I thought I was in trouble. Instead he took me under his wing and had me work with him after school on some fun projects! Really helped me understand that the skills I was learning were valuable and that I had an aptitude for it.
montecarl··on Protecting Secrets from Computers (2023)
https://dl.acm.org/doi/pdf/10.1145/3623614
montecarl··on Spotted water hemlock: the most toxic plant in North America (2017)
> People enzymatically convert corn sugar to match what comes out of sugar cane. Straight-up corn sugar is harmless, "high-fructose" is deadly.

Corn sugar is the monosaccharide glucose (more specifically its a specific stereoisomer of glucose called dextrose or D-glucose).[1] Cane sugar is sucrose, which is a disaccharide of composed of glucose and fructose.[2]

There is no way to enzymatically convert a monosaccharide to a disaccharide, you would need to be joining the glucose together with a fructose, which, as we are not fruit don't just have naturally occurring in our body.

When you eat sucrose, the enzyme sucrase-isomaltase located in the small intestine catalyzes its hydrolysis into fructose and glucose.[3,4] High-fructose corn syrup is a mixture of glucose and fructose which is exactly what you get when your body enzymatically breaks down sucrose.[5]

So corn sugar is glucose. Sugar can is sucrose. And high-fructose corn syrup is a mixture of "pre-digested" sucrose. I think that high-fructose corn syrup is probably bad in that its in everything and cheap, but I can't see how its any worse than regular sugar. And corn sugar is not the same as regular sugar, it lacks fructose entirely.

[1] https://en.wikipedia.org/wiki/Corn_sugar

[2] https://en.wikipedia.org/wiki/Sugarcane

[3] https://en.wikipedia.org/wiki/Sucrase

[4] https://en.wikipedia.org/wiki/Sucrase-isomaltase

[5] https://en.wikipedia.org/wiki/High-fructose_corn_syrup

montecarl··on Ask HN: Small-batch builds of smaller phyiscal objects
Sheet metal/waterjet cutting: https://sendcutsend.com/

chineese sheetmetal/cnc milling/3d printing (including metal): https://www.pcbway.com/

But if you can find a local fabricator that is probably best as they can help you understand if you design is manufacturable as is or if there are some simple tweaks that would make it cheaper/easier.

montecarl··on How to clean chemistry glassware
Because laboratory glassware is very expensive and that would be massively wasteful? Also, most labs that I have been in make regular use of custom made glassware. Most chemistry departments employ a glassblower! Also, for very sensitive experiments, you would most certainly want to clean even brand new unused glassware.

Glass is amazing for chemistry not only because it is chemically inert, transparent, has a high melting temperature, and is reasonably strong but also because it is easy to clean!

montecarl··on Love Notes to Newton [video]
Wow, the PCMCIA Megahertz dial-up modem shown at 2:22 in the video really brought back some old memories! I hadn't thought about PCMCIA cards in many years. Some of the first computers I used in the 90s were my Dad's work laptops and I thought those cards were so cool! I also remember using some 802.11b wifi cards on some old laptops with OpenBSD in the early 2000s back around the time that OpenBSD had particularly great support for wifi hardware at the time as compared to linux.

Anyways, I don't have anything to add about the Newton; I never owned one, but old technology can bring up some strong positive feelings about simpler times.

montecarl··on Make a low-cost Bluetooth LE packet sniffer with Wireshark
I an the sole developer of a product that uses bluetooth (classic not BLE) and have struggled so much with bluetooth (documentation and APIs just seem not that helpful or complete or are at such a low level that they aren't useful unless you already know everything), but I will try to give an answer and hopefully if I am wrong someone can educate us.

My understanding is that most bluetooth devices interface with the operating system over a standardized host controller interface (HCI) over a UART or SPI interface. Basically the OS sends some standardized commands to the HCI and receives some data back. This means that the OS doesn't have full control over the radio and are limited in what they can do to a set of standardized commands[1]. For example, even if you monitor everything that OS sends/receives over this HCI channel (using, e.g. btmon on Linux) you will not see everything that is going on.

For example, with bluetooth classic, during inquiry (discovering pairable devices) you don't really see all the details of what the device is doing. The hardware doesn't seem to signal anything about a host devices scanning you and the reply packets that are sent. I was trying to debug some issues with Windows 11 not discovering my device (despite it being in inquiry scan mode and that my phone could see it but not my desktop) and btmon was totally unhelpful in this case and I believe it to be a limitation of how the OS and the bluetooth device communicate at a fundamental level. It turns out the answer to my particular issue was the "class of device" that my device reported wasn't one that Windows 11 will show during pairing.

[1] https://software-dl.ti.com/simplelink/esd/simplelink_cc13x2_...

montecarl··on Longest-lasting incandescent light bulbs
This is easier to think about, if you consider the extremes. A very low power bulb generates no visible light, but still consumes energy. This is super inefficient. At higher temperature the peak shifts to longer wavelengths (i.e. visible). You can compare the black body radiation at different temperatures using Planck's law.[1]

[1] https://en.wikipedia.org/wiki/Planck%27s_law#/media/File:Bla...

montecarl··on Texas Power Prices to Surge 800% on Sunday Amid Searing Heat
https://archive.is/W6xmq
Page 1 of 13Next →