Protecting HDDs from (external) train vibrations
scrion @ scrion @lemmy.world Posts 0Comments 337Joined 2 yr. ago
scrion @ scrion @lemmy.world
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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:
https://www.scielo.br/j/lajss/a/ZnWZ8T86HHBLFvdksCh7g9s/?lang=en
https://www.mdpi.com/1424-8220/19/14/3143
https://www.mdpi.com/1424-8220/15/2/2980
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9824767/
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:
https://link.springer.com/article/10.1007/s00542-012-1592-z
https://content.iospress.com/articles/shock-and-vibration/sav00458
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:
https://www.youtube.com/watch?v=tDacjrSCeq4
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 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.
Eventually, you want to build a TMD: https://en.m.wikipedia.org/wiki/Tuned_mass_damper
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 https://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 https://www.mathworks.com/help/simscape/ug/mass-spring-damper-in-simulink-and-simscape.html , 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: https://www.amazon.com/Tertullus-Speaker-Isolation-Feet-Anti-Vibration/dp/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.
I prefer that it's not "flashy", it has the right mixture of looking rendered and photorealistic for a fantasy picture in my book. Also, visual context is provided (I can immediately make up a story for that encounter in my head) while being ambiguous or rather ominous to be widely usable.
On a sidenote, IMHO Midjourney has emerged as generating the highest quality AI images. Also, great that people constantly post their prompts here, I noticed a weird trend in guarding prompts akin to trade secrets, a ridiculous notion as far as I'm concerned.
I played that game when it came out and loved it, naturally - it was pretty revolutionary when it was released, 3d graphics and all.
Later on (say 15 years ago) I got nostalgic and tried to play it again, but couldn't get over the weird controls and camera angles and deemed it unplayable.
Funny enough, I remembered it a week before Christmas and re-played it in DOSBox. To my surprise, I actually made fast progress and didn't even die in any fight until midway into the game. I had a totally different experience in terms of difficulty, clunkiness etc. and really enjoyed it.
Yeah, you're right - the face definitely has more character and feels less derivative, but the background and general composition of the gremlin picture are just perfect.
This actually highlights my major complaint with AI image generation right now, the lack of a mechanism to combine certain features or tweak parts of the image to get where I want it to be. img2img etc. is helping and I'm sure we'll eventually get there though.
It is indeed pretty perfect. I would have run with it and edited out the tail by hand. That can even be done with infill AI as well, if one would be lacking the skill.
Right? Totally looks like a Melon.
A couple of months ago, I was wondering when we would come up with useful, real-world applicable usage scenarios for AI image generation.
I no longer wonder.
Yeah, that is about what happened. According to the BBC, he had purchased a keyboard, mouse and Fire TV stick to "connect to cloud services":
In a "flagrant disregard for his bail conditions", jurors were told that police found an Amazon Fire Stick in his hotel TV allowing him to connect to cloud computing services with a newly purchased smart phone, keyboard and mouse.
https://www.bbc.com/news/technology-66549159
Naturally, almost all "news" sources cook up a headline like "hack carried out with only an Amazon Fire Stick". Ugh.
Not everyone has to be neurodivergent to not want to use a credit card on the Internet - there have been plenty of leaks for this to be a valid stance. Also, let's not forget about other countries where credit cards play basically no significant role in day to day payment activities and people view them as "oddities" (for a lack of a better term).
Also, depending on how you hand your credit card info over, and if mechanisms like EMV 3d secure are in place, some merchants basically obtain a copy of your card and it's on you to check the validity of the transaction and also re-check that no additional transactions have been made over time. While it is certainly good practice to go over your credit card statement each month, I could totally understand if someone wanted to avoid that hassle and the one that comes with a dispute.
Let me chime in. Like many, I started with cheap printers (< $200 range) like the Anet or Ender models. While they produced results, instead of 3d printing enabling whatever purpose or hobby they were bought for, figuring out the printer (and its issues) suddenly became a hobby of its own.
That was fun for a while and I learned a great many things, but fixing bed leveling issues for the 47th time can get tiring when you just want to get that one print out that would fix the project you're actually working on. So I caved and shelled out the money for a Prusa.
In turn, 3d printing has become an enabler again. Don't get me wrong, I do get failed prints every now and then (about 1.5 per year in fact, statistically speaking), but I can immediately trace the error down, and so far, the source of the error has always been the one typing this comment.
Now, on to the filament. After a move I dug out some really old filament that had been sitting out in the open in my previous office for years. Mind you, that means approximately 58% relative humidity with an average temperature of 40F / 22C where I live, so overall the conditions were not horrible. Still, filament is hygroscopic and did apparently pick up all kinds of moisture - I was getting really bad prints, and on my holy Prusa of all things. I was shattered.
Well, long story short, I bought a cheap, one-spool filament dryer on Amazon (Sunlu something something version 2) in a flash sale for like $40 and the issues disappeared.
Moral of the story, no, not even a Prusa with all its reliability can protect you from moisture bubbling and explosively turning into steam in your extruder. Filament drying often does help though.
Looks great! Forgive me for sleuthing, but I tried to obtain more info about the glue shown in your picture, as I have never heard of that particular brand. From what I understand, it's a solvent-based glue that melts plastic parts together. They claim it works with ABS, which I can readily believe, but what's your experience with PLA, ASA or other materials? I'm wondering if the solvent does in fact melt those materials (and PMMA).
Btw. I assume it's "Ruderer L530", based on what I could see of it.
Hm, I never had any hardware issues in the last ~10 years, but don't get me wrong, I hear you. I absolutely believe that it is possible to find a combination of HW and SW that will simply not work for a particular use case, and if my productivity would be threatened, I'd also switch in a heartbeat. In fact, I've gotten so used to the customizations Linux offered me that I can't even imagine working on another Linux system without my setup and dotfiles - a different kind of vendor lock-in, if you will.
Anyway, just wanted to put a brand out there that offers some guarantees when it comes to hardware support, in case you (and others) might not be aware of such vendors.
I used to be a Windows system developer, think device drivers etc. for what, 20 years? I switched to Linux 18 years ago and never looked back - the whole dev experience is a lot more pleasant, more control, reasonable tools and software installation, proper customization etc.
I believe you didn't have a Linux problem, you had a problem with hardware manufacturers being fussy about enabling development of proper support for their hardware. Why not look into hardware that is actually readily compatible with Linux? Tuxedo Computers are often recommend, I used to run a Clevo and had a great experience as well.
Dude, super happy that you find so much joy in that picture, it's great seeing someone enjoy their hobbies and interests.
I feel no one has pointed out what makes the armor work, i. e. the rough, heavy cloth, really makes it look medieval - at least it's the combination of that cloth and the leather that sells it for me.
May I ask what fabric you used? Some raw cotton or linen?
I see depth and pose information. Dif you generate those using a model? If so, which?
You know what, this post finally made me sign up for an account - wanted to say thank you, I was indeed interested in the source image, so thanks for proactively providing that. Will check out the anime, too.
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.
https://phyphox.org/sensordb/
However, I think we agree this should be solvable without much theoretical effort.