fellerts's comments

On: Microwave Oven Failure: Spontaneously turned on by its LED display (2024)

[fellerts]

  I’m surprised that they chose to add a bunch of components to feed the AC line frequency to the microcontroller instead of just using a 32.768 kHz crystal. A single crystal oscillator seems like both the cheaper and more accurate option

The power line frequency is carefully monitored and adjusted to ensure that deviations from the ideal (60 Hz in OP's case) are smoothed out [0]. Even a single ppm deviation equates to 2.6 seconds per month, and your cheap 32.768 kHz crystal is going to be orders of magnitude worse than that.

[0] https://en.wikipedia.org/wiki/Utility_frequency#Stability

[jonathanlydall → fellerts]

My microwave seems to gain minutes per month, my assumption was that it's due to incompetency of Eskom, the essentially sole producer of South African electricity. With the government and parastatals here incompetency is very common.

However, out of interest I just pulled yesterday's stats from my inverter on Sunsynk's website. It has the frequency of the grid at 5-minute intervals and the average over the whole day was 49.975Hz which doesn't strike me as particularly bad, so I have to wonder if the Microwave itself has an issue. It's a Samsung which is now 13 years old.

[Joker_vD → jonathanlydall]

> the average over the whole day was 49.975Hz which doesn't strike me as particularly bad.

A day, having 86_400 seconds in it, is equivalent to 4_320_000 pulses at 50 Hz. At 49.975 Hz, it's only 4_317_840 pulses which is 2_160 pulses too few. Which, at assumption of 50 Hz, translates into discrepancy of 43.2 seconds, in this one day.

So, no, it's a pretty big discrepancy actually, over here anything over 0.2 Hz is legally declared to be "degraded quality", and it's been debated for years that this is actually a way too wide margin but the electricity providers/grid operators managed to successfully argue that they can't afford upgrades.

Moral of the story: don't get cute when designing electronics, just use AC/DC power supply and put a damn crystal oscillator as every other reasonable person.

[jonathanlydall → Joker_vD]

I'm guessing you're being downvoted largely due to the "don't be snarky" rules.

You're right (by my maths too, which I only did now) about it being a discrepancy of 43.2 seconds per day, which as you say is quite high.

However, it is my understanding that most grid operators are actually very good about maintaining a 50Hz average over a day specifically for devices doing time keeping based their frequency, I've heard they intentionally run the generators faster or slower at certain points in the day in response to needing to get the average right over a day.

I used to have no issues with time drift on my microwave, only started in the last few years.

On: Show HN: Whosthere: A LAN discovery tool with a modern TUI, written in Go

[fellerts]

I think this package does exactly what you need: https://pkg.go.dev/github.com/google/gopacket/routing. Works on my machine (error handling left to the reader)

    router, _ := routing.New()
    iface, _, _, _ := router.Route(net.ParseIP("8.8.8.8"))
    fmt.Println(iface.Name)

this prints my Ethernet interface as expected. It doesn't make any requests, it just figures out where to route a packet. I guess it interfaces with the OS routing table.

[rvermeulen98 → fellerts]

Thanks for sharing! This is definitely something I will look into, I am all in favor to simplify the current implementation of finding the "default" OS network interface.

[contingencies → rvermeulen98]

You'd better use the default route and not some random IP, particularly DNS IPs which people often meddle with.

  # IPv4 default route only
  uname
  Darwin$ route -n get 0.0.0.0 | grep interface | cut -d ':' -f2
  Linux$ route -nv  |grep ^0.0.0.0 | awk '{print $NF}'

On: Show HN: Whosthere: A LAN discovery tool with a modern TUI, written in Go

[fellerts]

That has nothing to do with the UI framework. The X11 dependency comes as part of the clipboard integration (which I'd argue should be optional or even removed). Still, I wouldn't call it modern if Wayland is outright not supported.

[rvermeulen98 → fellerts]

I think this is only a problem when building from source, right? It is indeed because of the dependency on https://github.com/golang-design/clipboard.

I hesitated a bit bringing in this feature. On one hand, I really like to have clipboard support, on the other hand, I don't like that it requires you to change from static to dynamic linking (and have the x11 dependency).

Maybe I could write an install.sh script for installation that detects the OS and fetches the correct version/tarball from the Github release.

[Daviey → rvermeulen98]

That library isn't going to support Wayland any time soon, and requiring CGO isn't ideal IMO. See this bug, https://github.com/golang-design/clipboard/issues/6

How about this PR? https://github.com/ramonvermeulen/whosthere/pull/29

It switches to using github.com/dece2183/go-clipboard, which supports Mac, Windows, Linux (X11 + Wayland) and Android.

[rvermeulen98 → Daviey]

Thanks a lot for your contribution, this is something I will look into in the upcoming days. I totally agree that CGO isn't ideal, I had to make the build/release process also a lot more complicated purely for that clipboard requirement (see GHAs and the different goreleaser files).

On the other hand, I also don't want whosthere to be depended on a fork that isn't maintained anymore. I will think about this trade-off, but I am also interested how others look at this problem.

[ok123456 → fellerts]

What's modern about Wayland?

On: Hacking a Casio F-91W digital watch (2023)

[fellerts]

Cool project. Tip: acetone will readily dissolve the plastic parts of the card leaving the antenna(s) and chip intact. I believe a few other people have made drop-in PCBs with NFC antennas. Here’s one: https://n-o-d-e.net/datarunner.html

Also, no F-91W thread would be complete without a mention of the sensorwatch project: https://www.sensorwatch.net/

[dmaa → fellerts]

The dissolution in acetone is nicely demonstrated here https://youtu.be/NF4VJJKTjy8?t=835 The guy does it in order to be able to pay with a prosthetic eye.

[afandian → dmaa]

I would like to encourage everyone to set some time aside, get comfy, and watch Bobby Fingers. His videos are extraordinary, special, things.

I think making a giant Jeff Bezos boat would appeal most to this crowd, but I'd suggest watching them in order.

[piltdownman → dmaa]

For anybody wondering wth is with a guy sculpting dioramas about obscure celebrity misadventures - he was formerly half of the Hip-Hop Comedy Duo, Sketch Artists, and behemoth Irish podcasters 'The Rubberbandits'. Probably one of the greatest neo-dadaists and proponents of Aestheticism in Europe today.

https://www.unitedartsclubdublin.com/post/bobby-fingers-the-...

Some might even know them without realising it - their incredibly provocative Richard D. James-esque 'Dad's Best Friend', a sonic assault about isolation and toxic masculinity, was featured prominently in the Trainspotting Sequel, "T2"

https://youtu.be/iYgPznBrjiA

[alejoar → dmaa]

This is hilarious!

On: AI is making us work more

[fellerts]

The peak is a handful of requests per second. If you have a static site, the cheapest Hetzner tier handles it just fine.

On: Mechanical Watch: Exploded View

[fellerts]

Most services just include cleaning and relubrication. Parts don’t wear out that quickly.

Most watches from before the quartz crisis (pre ‘70s) used standard off-the-shelf Swiss movements for which spare parts are still readily available. It can get tricky with expensive or rare in-house stuff like Omega and Rolex though.

On: Mechanical Watch: Exploded View

[fellerts]

https://fabianoefner.com/cutup/

[dsalzman → fellerts]

Hmm. I think he sliced it after he encapsulated it. Or that's my memory! So he had a "book" of cut acrylic sheets/layers of the object.

[dsalzman → dsalzman]

You are right! Was thinking of the same artist just a different project he did. https://fabianoefner.com/the-bialetti-book/

Video on the project https://vimeo.com/354927033

On: Mechanical Watch: Exploded View

[fellerts]

The minute hand is set to 43-ish minutes past the hour while the hour hand is showing 15-ish minutes past noon/midnight. If you’re used to reading analog watches it’s jarring.

On: Mechanical Watch: Exploded View

[fellerts]

Watch a few hours of watch repair on YouTube. If you're still intrigued, I highly recommend Mark Lovick's course over at https://www.watchfix.com/. You'll learn all you need to know about tools, lubricants and techniques to service most watch movements.

On: Mechanical Watch: Exploded View

[fellerts]

It is remarkable indeed! When not ruining watches with resin I enjoy servicing them, and I'm planning to learn how chronographs work next. The ST19 movement is on its way now, another very reasonably priced, reliable and fully mechanical chronograph with a column wheel. Hats off to the Chinese.