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Cake day: June 12th, 2023

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  • If you want a preview of an uncaring and anti-consumer Valve, look no further than the company’s efforts on Mac.

    Valve never updated any of its earlier games to run in 64-bit mode… Apple dropped support for 32-bit applications in 2019

    Funny enough, the only platform with a 64-bit Steam client is Mac.

    I don’t disagree with concerns about monopoly, but the author’s key example is Macs. And from the example, it sounds to me like Apple disregards backwards compatibility (dropping 32-bit support, moving to ARM chips) and Valve isn’t investing to keep up. Meanwhile, Windows has a heavy backwards-compatibility focus, and Linux isn’t too bad either, so no wonder they still get Valve’s attention. So who is being “anti-consumer” in this example, Valve or Apple?


  • As I said to him, “in the US you don’t get to vote and get someone better than Joe Biden
    

    Actually, write-ins are a thing, so you literally can vote for anyone else than him and Trump.

    I think you misunderstood the author. You can literally vote for anyone, but the winner of the next US presidential election is only going to be Biden or Trump (barring a crazy twist, e.g. death or criminal conviction). I think the author’s point is that, in any given election, you should probably vote strategically, but getting better options takes a lot of work for a long time to make it happen, so get working if you can.




  • Thanks for the update and graphs. That is an amazing improvement. In the “after” plot, it looks like any acceleration from the train is well below the noise level of your accelerometer. So, within the limits of your measuring equipment, you’ve effectively eliminated all train vibration. If I were in your place, I would declare success and move on with life! Don’t even bother with foam and rubber feet, because this configuration is working great.

    But you could analyze further if you really want; there could be some train signal hiding in all that noise. Since there’s periodic noise in the Z axis, you could take a reading during a still time (computer off, no trains) and see where your spikes are in the frequency domain. Then you could apply a filter (or filters) to cut out that periodic noise.

    But unless you’re really into learning about signal analysis, I’d say you could skip it.


  • None of the included experiments look to be exactly what you need. For characterizing your isolator, the included Acceleration Spectrum is close, though it records continuously, making it difficult to use to record impact response. For evaluating actual train vibrations, the user-defined Integrated Acceleration might be a start, but it doesn’t include the filtering needed to get good information. You could define your own experiments, but that’s probably even harder than analyzing the CSV data on your computer. At least on your computer you can change your analysis freely and immediately see results, rather than re-running the experiment every time.



  • I work in railway noise and vibration mitigation, and @scrion@lemmy.world has given you a great starting point. When we build rails and want to mitigate ground-borne noise and vibration (typically up to ~200 Hz), we generally mount the rails on soft pads and add extra mass to isolate the rails from the surroundings. The exact same approach will work at your computer. We don’t typically use tuned mass dampers for ground-borne vibration, so I think that will be overkill for you, but you can try if you like.

    I wanted to suggest that, in addition to the feet/foam/plywood, you can also add a big chunk of something heavy to help with isolation. Like put a heavy rock on top of the foam, and your computer on the rock. The trick is this: if k is the stiffness of your foam, and m is the mass of everything on top of the foam, then your isolating frequency is at √(2k/m). All frequencies above the isolating frequency will by mitigated (the further above, the more they’re mitigated), while all frequencies below will be amplified.

    (Quick aside if you actually want to calculate frequency with √(2k/m): check that your units for k and m are compatible, you should end up with a result in units of 1/s, which is actually radians per second, then multiply by 2π radians per cycle to convert to Hertz).

    When it comes to measuring results, since your problem is in low frequencies, you can probably use your phone’s accelerometer assuming it reads fast enough (the sample rate must be at least double the highest frequency you care about). Mount it as rigidly as you can to your computer, since if the connection is soft, the phone will be in its own isolating system. The quickest way to test your isolator would be to hit close to the base with a hammer; impacts excite a wide range of frequencies equally, so in the frequency domain you should see vibration amplitudes following a shape something like these.

    But as @scrion@lemmy.world notes below, you don’t really care about your isolator’s response, you care about what trains are doing to your computer. However, he said one thing I disagree with: it’s not the amplitude of the acceleration that you care about, it’s the amplitude of energy, and therefore velocity. This article gives a good introduction to ways you could analyze that. But now we’re getting way in to the weeds on what should be a simple project!

    One last aside: if the vibrations in your building are bad enough, you could raise it as an issue with the metro operator. The US Federal Transit Administration sets standards that are commonly followed even outside of the US (see Table 8-1 in their Noise and Vibration Manual); if your measurements show vibration exceeding those limits then they might pay me to fix it :D.


  • randy@lemmy.catoxkcd@lemmy.worldxkcd #2867: DateTime
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    11 months ago

    I really wish that list would include some explanations about why each line is a falsehood, and what’s actually true. Particularly the line:

    The software will never run on a space ship that is orbiting a black hole.

    If the author has proof that some software will run on a space ship that is orbiting a black hole, I’d be really interested in seeing it.