K-9 mail… isn’t supported or being developed any more.

That’s not true. They make frequent-enough releases, they post monthly progress reports, and they are actually going to become Thunderbird’s Android version.

Having said that, I almost switched to FairEmail because K-9 lacked support for some sort of authentication measure (which I no longer need), but that wasn’t because K-9 stopped development.

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.

Wow, I hadn’t heard of phyphox before (hadn’t even noticed @khorak@lemmy.dbzer0.com mentioned it in the OP). That’s very cool and I’ve installed it now.

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.

At a glance, it looks like Aegis generates standard TOTP tokens, which means there’s a lot of software that can do the same thing, so you don’t need to emulate Aegis. I use pass-otp (an extension to pass), but that’s command-line-only, and a lot to deal with if you’re not already using pass. From a quick search, it looks like Keysmith and OTPClient are decent graphical alternatives. From another quick search, OTPClient is available in Ubuntu 23.10.

Edit: Re-reading your post, your issue is that you don’t like logging in on your phone, right? But Aegis just provides the code, you should be able to use the code from your phone to log in on your computer. TOTP codes are only affected by the secret values and the current time, so the code generated on your phone can be used on any device.

Tell us more about what you’re thinking of building/drawing. I like FreeCAD, but it’s also quite complicated, depending on what your goals are.