Not aware of any such project. I’d assume you’ll need some hardware anyways as you need it for the level of access (ATX etc.). Not sure how that would be preferable to this.
I was thinking more about the basics, like USB input and getting the image+sound. For that you could get away with a special USB cable and a capture card. I’m just not aware of any software for it, I don’t think the original PiKVM stuff was ever ported to PC.
Thank you, I managed to get it working with MediaMTX and DockoVPN I still don’t know how I would manage dynamic IP changes during the days I’m away, that would break the VPN
For the dynamic ip address that you can get a free domain name from afraid or noip or maybe others and point your vpn to your domain name instead of direct ip address. Following that you can run cron job scripts to ensure the ip address that the domain points to is up to date
Some systems (debian) may require this sudo usermod -a -G video www-data to make sure it will work. Because ffmpeg will be launched with the www-data user that doesn’t have access to the video cameras.
It will even turn off the camera if nobody is connected;
Use ffmpeg -f v4l2 -list_formats all -i /dev/video0 to find what formats your camera supports;
Watch the stream from VLC with the url: rtmp://device-ip/live/stream
I’ve been working on this on and off for a few months now. The more I learn, the deeper the hole gets. Ports and VPNs and UPNP and TCP and UDP and hosts and containers and firewalls and on and on. It’s a lot.
Many times I can’t get things working properly, if at all, and other times it works perfectly one day and then several days later, after changing absolutely nothing, no longer works.
My current goal is to get a Mobilizon instance and a Jitsi server running, to hopefully get a community started up there that meets up regularly to help each other, and to make onboarding easier.
I tried to ask for help around here and, while a few kind people did offer to help (and disappeared shortly thereafter), I was overwhelmingly lambasted for daring to ask for personal help.
I’ve been doing Linux server administration for 20 years now. You’ll always have to duckduckgo things. You’ll never keep it all in your head, even just a single server with a handful of services. Docker and containers really isn’t too hard. Just start small and build from there. If you can learn how the chroot command works, you’ve pretty much learned docker. It’s just chroot with more features.
Yep same here. Professional IT for over 25 years. Nobody knows everything. It’s ok to fail. Just keep swimming. And when you do get something working…. that high is unbelievable. It’s like a drug addiction and will drive you to do more and more. Good luck!!!
This. And, yt-dlp and/or youtube-dl used to have an issue where if the url started with the video ID instead of the playlist ID, it just downloaded the video not the whole playlist. Not sure if that is still around, then just be aware.
I have 3 Intel S3700’s, one for the OS and two 400GB ones for a mirror pool (might do a raidz1 as well). But getting anything in a serious capacity (8-12 TB of usable storage) with datacenter SSDs is really expensive. :(
Just rob a few banks, go to prison, meet a coke dealer, get out of prison and start selling coke, rise up the ranks until you can kill the current leader and become a drug kingpin, and finally realize that you still don’t have enough money for it because they are expensive as shit.
One big shared media volume has multiple benefits, each server just have to deal with their own user management, no server switching or remembering if that one movie is of this or that Server…
But this is by design, snap containers aren’t allowed to read data outside of their confinements. Same goes for flatpak and OCI-containers.
I don’t use snap myself, but it does have its uses. Bashing it just because it’s popular to hate on snap won’t yield a healthy discussion on how it could be improved.
Snap sucks, but not for the reason OP stated. There's a decillion reasons for why Snaps suck, why make up a reason that applies to other formats that are actually good?
Ok then don’t publish an application that clearly needs access to files outside of the /home directory. Or at least be upfront about how limited it is when run as a snap.
I have a 20TB RAID array that I use for a number of services mounted at /data. I would like Nextcloud to have access to more than the 128GB available to /home. I’m not willing to move my data mount into /home and reconfigure the ~5 other services that use it just to work around some stupid Snap limitation. Who knows whether Snap even can access data across filesystems if they’re mounted in home. I wouldn’t put it past the Snap devs to fall down on that point either.
Yes, Docker clearly needs access to all files. It is meant for running server software, and server software is supposed to be flexible in its setup. To me, this limitation makes it completely unusable. Nextcloud is only the first service that needed access to that directory. I’ll also be running MinIO there for blob storage for a Mastodon server. I’ll probably move Jellyfin into a Docker container, and it’ll need access too.
The fact that this giant issue with Snap is not made clear is my biggest problem with it. I had to figure it out myself over the course of two hours when there are zero warnings or error messages explaining it. What an absolutely unnecessary waste of time, when it could have warned me at install that if I wanted a completely functional version of Docker, I should use the apt package.
I will never use any Snap package again. This was such a bad experience that I probably won’t even be using Ubuntu Server going forward. I already use Fedora for desktop. And the fact that a few people here are basically saying it’s my fault for not already knowing the limitations imposed on Snap packages is just making it more obvious that Ubuntu has become a toxic distro. It’s sad, because Ubuntu got me into Linux back with Hardy Heron 8.04. I’ve been running Ubuntu servers since 9.10. I used to be excited every six months for the new Ubuntu release. It’s sad to see something you loved become awful.
The issue here is that Canonical pushed the snap install without warning about its reduced functionality. I don’t think highlighting a wildly different experience between a snap install and the Docker experience people are used to from the standard package install is “bashing it just because it’s popular to hate on snap.” For example, if you take a fresh Ubuntu server 22 install and use the snap package, not realizing that snaps have serious limitations which are not explicitly called out when the snap is offered in the installation process, you’re going to be confused unless you already have that knowledge. It also very helpfully masks everything so debugging is incredibly difficult if you are not already aware of the snap limitations.
I believe it doesn’t really matter much whether you want to protect the environment from vibrations of the machine vs. protecting the machine from vibrations of the environment - in both cases, decoupling the systems is what you want to achieve.
I personally had to deal with the case of a large format CNC machine transferring stepper motor vibrations into an adjacent office via the wall-mounted brackets it was sitting on. People started to complain shortly after installation since the noise was very audible in the otherwise quiet working environment.
The solution involved placing the machine on a plate mounted via rubber decouplers (see www.dayco.com/en/product/decouplers) which in turn was mounted to a shop-built TMD using a rubber core sandwiched between two foam plates. The rubber core works as both mass and absorbs additional vibrations. It was built following a paper, but unfortunately, that was around 7 years ago and I’m not sure I’ll be able to dig the publication out again.
You can in fact simulate the TMD and do the tuning (see for example mathworks.com/…/mass-spring-damper-in-simulink-an… , though dedicated software packages also exist) but in all honesty, that will probably be overkill for your case.
Having your NAS sit on a 1/2" board of baltic birch plywood resting on a foam sandwich is probably going to do the trick in your case. You can easily create such a sandwich using foam, a rubber mat and some spray glue. Different foam densities will give different results and yield different “tunings” - you may have to play around with this a bit. I could imagine you’ll most likely even be able to skip the second decoupling step (rubber feet/decouplers), in the aforementioned case the second decoupling allowed for another set of frequencies to be dampened (via a different overall rubber hardness) but also brought overall amplitude down.
Don’t use super soft foam, as this will yield a wobbly base, something you probably want to avoid for your NAS. Also, make sure not to attach the base board to anything else apart from the foam, or you’ll transmit vibrations again. If you don’t like the appearance of the foam, you can build a small fence around it that goes up to the top of the base plate.
All that being said, there are also ready-made solutions like speaker dampening feet available: www.amazon.com/…/B09QC2L7N3
Most of them are made to decouple subwoofers, so they might fit into the frequency spectrum you specified. Those couls certainly be an affordable and rather quick way to solve the problem.
Awesome, thank you for taking the time to include so many details. I can see myself easily building the aforementioned plywood+foam sandwich platform, sounds like a more solid platform to put the NAS case on (mid tower).
The subwoofer feet also look fun, I remember reading about them back in the reddit days. After revisiting my notes and the post, there were some concerns about harmonic vibrations and oscillations from the drive having an negative impact. But reading it again, I don’t think that this will be a problem.
I think I’ll start with the feet and see how they perform while I source the plywood and foam. Maybe there are also some foam / rubber mounts for the disks themselves, I should be able to find suitable one as it’s a more common problem to have.
Do you have recommendations for how I should best measure the results? Preciously I looked into the raw acceleration data to see how strong the vibrations are, and then I looked into the spectrum to find the vibration frequencies. All with consumer / noob friendly tools (phyphox), hoping that the change will be measurable and the results - meaningful.
Honestly, I think your approach using the MEMS accelerometer in your smartphone is fine - just make sure to tape the back of your phone firmly to the board to get a rigid connection. This will be of particular importance if you want to do any kind of tuning, as you might measure spurious frequencies if the device is not properly attached.
Smartphone accelerometers are actually used in civil engineering / industrial applications to determine frequencies of e. g. bridges or check for bearing wear. If you are interested, here are some papers:
That being said, the accuracy of the frequency readings is not super important for your application, as what you are after is pretty much only a reduction in amplitude. I would assume spinning hard drives show different responses to different vibrational frequencies, but I did not have the time to research this myself. However, here are two papers that explore what you are trying to do, which I will link since they also mention a few related papers that show the impact of vibrations on hard drives:
This would in theory incentivise to optimize dampening certain frequencies, but I suspect you will quickly get into the realm of overengineering / premature optimization, as the dampening might be good enough to tune out all relevant frequencies without simulations or tuning etc. However, it’s still certainly a worthwhile effort for educational purposes though.
As for a practical approach, I’d probably simply start out with some super cheap foam obtained at the nearest home improvement or crafts store and see how a sandwich using that affects signal amplitude. You could even introduce artifical vibrations using a DC motor with a weight mounted off-center on the shaft, which you can get ready-made for next to nothing on eBay (“vibration motor”, ~ $2).
If you want to get into tuning / experiment / analysis territory, I would like to include additional motivation. Not only might proper decoupling increase the lifetime of your drives, but it could also improve performance. I will include the following video as humorous proof of that:
P.S.: I firmly believe that research should be freely accessible, so I feel obligated to mention that all papers linked above are, if not available for free on their respective webpages, obtainable via a certain scientific hub.
I work in railway noise and vibration mitigation, and @scrion 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 https://commons.wikimedia.org/wiki/File:Amplitudenfrequenzgang.tif.
But as @scrion 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.
Hey, great that you chimed in, I agree with the points you’re making. As for my remark regarding amplitude, what I wanted to convey was: in the measurement scenario using the PhyBox smartphone app, OP should see an overall smaller signal envelope if the NAS was properly decoupled, compared to the previous plot.
As for your comment regarding the Nyquist theorem, PhyBox maintains a list of devices and their sensors so it would be possible to lookup the available sampling frequency. There are other factors potentially limiting the sample rate (e. g. switching offl microphone access for the app on Android), but it’s a good starting point.
I’m wondering, now that you’ve seen the app, do you have some practical advice on how to measure the difference without having to spend a few hours researching and refreshing on high school physics? It seems that my only option is to run the “Acceleration without g” experiment and work on the csv export.
A probably naive approach would be to filter out values below a certain threshold (a ‘low pass filter’ of sorts to deal with a noisy sensor) and then try to meaningfully sum the acceleration by time period. But just as I wrote this I realized that I can’t simply sum a few values from several rows and call it a day.
The article you linked explained the idea behind the pseudo velocity well, I’m wondering if I can… “sum the area” (assuming interpolated data) under the various measurement points. Without completely nerding out and investing too much time :D My sensor seems to have a rate of 200Hz, so it should be good for measuring vibrations up to 100Hz.
Edit, it’s integrals, right? This is actually exciting, haven’t touched math since university. Also here’s an example of how the acceleration graph looks like when the phone is on the heating / radiator (more or less worst case): Screenshot from phyphox with acceleration sensor data
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’ve been a bit busy so I haven’t had the time to figure out what and how much I need to compensate so the sensor data is more useful. One of the sensors seems to be detecting something reminiscent of a sine curve, so this will involve some extra high school math to find a function to cancel it out. Busy dad etc, maybe next week. In the mean time I started putting together the case and ordered the springy subwoofer legs. Here is how a simple plot of the raw acceleration looks like.
It’s obvious which one is the before and after. The second one even includes two trains arriving back to back.
Now I need to figure out a few things:
repeatable experiment (hammer? dropping something heavy from the same height?)
make the Z-axis reading more useful and compare velocities
add some foam/plywood and rubber feet on the disks
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.
Cisco do free networking courses which teach the fundamentals. The one I did was more theoretical than practical but it really helped me think of what Im really trying to achieve and learning the terminology was really helpful, especially later when trying to troubleshoot and finding help online that was a struggle before the course.
There are assessments as you progress and a certificate at the end.
They also have virtual software you can play around with for different potential configurations. Thats much cheaper than buying lots of hardware!
selfhosted
Newest
This magazine is from a federated server and may be incomplete. Browse more on the original instance.