Hard Drive shock protection
 

I'm working on a project in which I will be mounting a desktop computer on a lawn mower to control it. I'm worried that I will be running the risk of damaging the hard drive from all of the vibration. Has anyone ever killed a hard drive from vibration? How long and intense can vibration be before there is serious damage? Also, what can be done to protect a hard drive from vibration, I've found a few ways but I want to know what others are out there.

This website has a description of how hard drives are normally damaged.

-Alan

Re: Hard Drive shcok protection
 

A few questions before any real answers can be given:

1) What speed (in RPM) is your hard drive? Lower is better for this; SCSI is NOT A GOOD IDEA. Is flash media an option? Several different *nix distros can fit on a 2gb card, and vibrations wouldn't even bother the card.
2) How strong are the vibrations from the lawn mower?
3) How much would you be running this?

Re: Hard Drive shock protection
 

Re: Hard Drive shcok protection
 

Well it is an IDE hard drive, I think 7200 RPM. Infact I will be running Linux on it but I have not considered flash storage. So far I've just been using parts that I could find laying around my house and school. I have a few old CDrom drives, maybe I could make a LiveCD. Maybe vibration would be less of an issue for a CD drive. How much do 2gb flash cards cost and where can I buy them?

I don't know how strong the vibrations are. How could I go about measuring it?

Well my end goal is to have this system cut my lawn autonomously (I've really gotten lazy about cutting the grass) so it will be run for about an hour at a time.

Re: Hard Drive shcok protection
 

CDs would probably be more sensitive to vibrations, (think of a CD player without skip protection) but they won't actually get destroyed. Because it's likely that once the base system and the lawn cutting program load you won't need to be retrieving more data, it would probably work fine. (Esp. if the cdrom spins down after that.)

Interesting idea. I might try that too...

Re: Hard Drive shock protection
 

I had to do this on our DARPA grand challenge car. after much review we opted to go for solid state flash drives, although if that is not an option (cost, memory size) defiantly use laptop hard drives as they are much less affected by vibration.












edit: 1000th post

Re: Hard Drive shcok protection
 

Flash is definitely a good idea, in fact much better than a hard drive, for something like this. Think of read/write heads moving a couple thousandths of an inch above the surface of the platters, containing data which you need, and then think if you've ever seen a smooth-running lawnmower (or any smooth-running 1-cylinder engine, for that matter). It's similar with CDs; by getting my read heads out of alignment on one drive (I was adjusting it because it wouldn't read reliably), I managed to have it cut concentric rings in a disc, because the head was dragging on the surface. You will too, if you try to retrieve data from a CD, only they won't be so evenly spaced, as the drive seeks back and forth over the entire surface, and bounces wildly.

Windows 2000 fits on a 2 GB card too, provided that it's properly pruned down (to leave a couple hundred MB for swap space); you might need to install to a larger drive (which you have), delete extra stuff, then image it to a card. Then again, Linux works too, if you prefer.

In any event, any computer store will carry (or be able to get) the appropriate size of compactflash card; compactflash is pin-equivalent to ATA, but uses a smaller connector, so a simple pass-through adapter will allow it to be used with any common motherboard through the 40 pin connectors. See here for the card, and here for the adapter for example.

Also, I can't help but correct this: SCSI is a bus specification. It is not an indication of shock resistance. Modern SCSI drives are often built with high spindle speeds, but older ones can be had with much slower spindle speeds; I've worked with a 4.3 GB, 4200 rpm SCSI drive, and a brutally slow 200 MB SCSI drive from the mid 1990s. Though I agree that it seems sensible enough that peak spindle speed and vibration resistance may be linked, I'm not sure that the correlation is significant, especially compared to other characteristics of the drives' designs.

On the ArsTechnica Forums, they have a procedure for dealing with people who brag about multiples of their thousandth post. Ask about the "DoD" in that forum's "The Lounge" section....

Re: Hard Drive shock protection
 

I realize that if your looking for vibration resistant media, flash would be your best bet. However, I'm a little weary about using flash as the primary storage on a computer. My concern is wearing out the cells. Flash can only go through a finite number of read/write cycles. For something like a camera, it's fine because you'll usually fill up the card before erasing it. A computer however, will be constantly changing data. A file that's rewritten very often (maybe a log), it would wear out the flash very quickly.

Re: Hard Drive shock protection
 

That's always been a concern with flash memory technology, but since he only intends to use it for an hour a week, and because most of the activity should be taking place in RAM anyway (since there's not really much need to page data in and out, except to load it the first time it's needed—and even that is only a read), I doubt that he'll see any trouble, unless he's writing huge amounts of data in his log files. His usage pattern is (presumably) so different from that of a normal computer, that usual caveat shouldn't really apply. In any event, flash memory tends to have at least a few hundred thousand rewrites per cell (on average), and some good-quality, modern cards are reputed to be capable of millions of rewrites.

Re: Hard Drive shock protection
 

Do you really need a full computer? Or a full computer on the mower? what do you want to do with the mower and the program? Could you get away with something like a microcontroller? If that wouldnt be enough, you could take a linksys WRT 54G wireless router, which runs on linux and has many other 3rd party firmwares, and is open-source also. Add a SD card, and use the GPIO's on it to interface to the mower. http://kiel.kool.dk/

Plus then you have wifi built into it, and you could do neat stuff like call the mower in if the weather turns bad... etc..

EDIT: just to get you thinking... http://yasha.okshtein.net/wrt54g/

Re: Hard Drive shock protection
 

Would something like an iPod work?

Re: Hard Drive shock protection
 

Do Ipod's really have that much protection around the drive? They didnt look like it from the things Ive seen online when they are opened up.

One thing to remember about shock absorbers, if you do decide to go the route of using a full computer, they need to absorb the shock, not convert it into oscillations. A lot of the things that I have seen online for hard drive shock absorbers involve rubber bands. They end up having the hard drive there oscillating after the bump, which is almost worse (if not, actually worse) than the initial bump. The shock absorbing mechanism in that video in the first post was amazing, the drive moved down and back up, once and stopped. That is what the shock absorber should do.

Re: Hard Drive shock protection
 

Well the new nano is actually a flash drive and I seem to remember (can't place my finger on where) reading about someone rigging a Ipod to run an operating system. Anyways, have you actually tested if the vibrations will cause problems. As it was mentioned before, a hard drive probably wont be damaged by the vibration unless screws come undone (not likely). If it does start to skip on you you might want a foam. Try running your computer and see what a hard drive will take before it skips (I know Ive dropped computers while they were running and had no trouble but the constant vibration might be an issue).

Re: Hard Drive shock protection
 

http://digitalmedia.oreilly.com/pub/...ks.html?page=3

you mean this? :D

But I don't advise ueing an IPOD as a bootable drive becase those hard drives are only rated for 20,000 hours or so

Re: Hard Drive shcok protection
 

Flash is definitely the way to go - if you have a 512 meg usb flash and a motherboard that supports booting from it, you should be able to get linux running on that. As far as for windows, you would need at least a gig assuming a very small page file. I would avoid using a hard drive as much as possible in this situation.

Also, depending on your cost limit and the performance you need, you might want to consider an embedded system like a gumstix unit.

Agreed - and SCSI drives are built to much higher standards as they are usually run 24-7-365 unlike most IDE drives, and need to be reliable in the enterprise environment (and you don't have to tell me about how you run your pc's IDE drives that often, because they will fail - I've had my share of failed ide drives from various mfg's).

Re: Hard Drive shock protection
 

I've been trying to stay away from flash media because of the read/write limitations and the fact that while the computer is not driving the lawn mower it would make a decent desktop PC. But since I have not really started the software development yet, I can design to minimize reads and writes, which should be farely few anyways.

Well the main reason for a full sized PC is that I wanted to beable to have remote control over the internet with streaming video and a MicroATX PC seemed like a good control system. I looked into using a microcontroller but it just seemed more advantagous to build PC for ~$300 that does what I want and more than settle for a ucontroller that did most of what I want for 1/3 -1/2 the cost of the PC. Also, with a PC I can keep adding sensors and do all kinds of image processing until my heart is content. May not have been the best choice but thats what I've got. Wow that Linksys RC car is pretty sweet... now that would be awesome on a Nitro RC car!


As I look at the prices of flash media, laptop harddrives are starting to look very attractive. I found the specifications for a laptop harddrive and I don't think my lawn mower will approach the maximum shock or vibration rating but I need to be sure, any ideas on how to measure it? :confused:

Re: Hard Drive shock protection
 

For measuring shock, like bumps, maybe an accelerometer would work, like something you might use in physics. Hooked up to one of those vernier lab pro computer things, you could probably get a fancy graph and find the shock force. I guess that could work for vibrations too maybe? Just a thought

Re: Hard Drive shock protection
 

Do you think the accelerometer in last years kit could work? I don't think my school has an accelerometer for lab use, I'll check tomorrow.

Re: Hard Drive shock protection
 

Not for measuring 300G - IIRC its a 1.5G (in each direction) accelerometer.

Re: Hard Drive shock protection
 

Flash sounds like the way to go especially hearing about the compact flash and 40 pin connecter. i know this goes against what i just said but it may help. hitachi makes a hard drive CF card (if you think about this for a second and think about the "compact flash part it doesnt really make sense since its a hard drive) it has a really high shock protection and may be eaiser to shield from vibrations. cons are its kinda pricey----if it works you could start a lawn mowing business and profit on it.

Re: Hard Drive shock protection
 

Simple fix for this. Take a piece of insulation foam (go for half inch thick), and mount the hard drive bottom to it. Then, take the same foam and cut blocks about 1 inch square out of the same type of foam, mounting them to the bottom of the foam on the hard drive. Another full sheet on the bottom of the hard disk and it'll be good to go, just attach the very bottom piece somewhere on the comp case.

I'm pretty sure this'll work, but not 100%. The vibrations of a lawn mower on the ground may be a little more than a motor boat engine a friend of mine modified. The foam should dampen most of the shock to the HD, but you might want to increase the thickness of the blocks, to give it more room to move.

Re: Hard Drive shock protection
 

Like this?

Sounds like a good solution but I'll probably need to do something about heat dissapation.

Re: Hard Drive shock protection
 

bingo. hard drives will produce a fair amount of heat when running for long periods of time and you need to think about airflow around the drive for heat dissipation. If you are going to do something like this, I would consider getting a hard drive enclosure and foam mount the enclosure instead of the drive itself.


you also need to figure out if the foam will work, remember 1 hit to the platters and the drive might be dead.

Re: Hard Drive shock protection
 

Yah, that would work. The main thing is that whatever the HD is attached to is insulated from shock. A fan or two mounted on the HD mount would help the temp, and take care of it. The foam would make it so that HD is sheilded from vibrations.

Re: Hard Drive shock protection
 

I'm curious, how were you going to power it?

While hard drives are the most obvious targets of vibration damage, theres more to be worried about.

While most of the PC is solid state, none of it is 'shock/vibration proof'. Everything from the power supply down to the screws holding the motherboard to the case could be damaged from prolonged vibration. R/C plane builders know all about just how damaging vibration can be to even simple solid state electronics, and will wrap receivers in latex foam and servos are often shock mounted. High vibrations can crack solder joints, work heavy capacitors loose, loosen heat sinks, knock a RAM module out etc.

My guess is that even if you don't see a hard drive failure, you will see one somewhere else. I'm sure its possible to do this, and I think it has been. However, the desktop PC wasn't made to move around. And being bolted to a lawn mower is about as terrible environment as I can think of.

My suggestion is to look into buying an old laptop, perhaps a Toughbook. A laptop has been designed to move around and deal with a life of being dropped. You'll still have to do something about vibration, but at least you don't have to worry as much about powering it.

And be careful about advertised 'shock' and 'g loads'. Usually these numbers refer to a devices ability to handle drops when off. A spinning hard drive is much more apt to be damaged then one that is powered down.

-Andy A.

Re: Hard Drive shock protection
 

The thing with flash memory is that it is much more expensive than a hard drive. Recently, I saw a DARPA car that had mounted the computers on tensioned wires, which, in turn, absorbed the shock produced by the terrian and the car.

Re: Hard Drive shock protection
 

Being an OS programmer, my instinct would be a flash chip on a motherboard that supports booting USB devices: if you're willing to pick up an assembly book, you can write your lawnmower control program in a matter of kilobytes. If, on the otherhand, you prefer something like Linux or Windows, why not just make the lawnmower tow the computer (on wheels) behind it?

Re: Hard Drive shock protection
 

There is the "Why didn't I think of that" idea!

Wetzel

Re: Hard Drive shock protection
 

Hmm, I do have a cart that can be attached to my lawn mower, plus I have been running into some space issues.

Re: Hard Drive shock protection
 

Yes, maybe you might want to make a laptop HD a consideration, those are supposed to be less sensitive to vibration than desktop HD's...

Re: Hard Drive shcok protection
 

OK... You CAN make a windows live cd, as I have one in my computer repair kit, therefore it stands to reason that you can make a windows live flash drive. as for the gig of storage needed,right now the CD is about 530mb, but that is with a a whole crapload of drivers (for universal detection) and programs such as Spybot S&D and Adaware, along with alot of other utilities. I could probably get the file size down to 1-200mb. Also, converting an impact into circular movement is most definitely better for a hard drive than the original impact. I've only had one harddrive quit on me, and that was when I dropped it from to top of my staircase (don't ask).

Re: Hard Drive shock protection
 

Sorry to refresh such an old thread but I get subscriptions to PC-Stats and just saw this today LINK More or less this idea of running a desktop on a heavily vibrating object is no longer a worry! This also has TONS of potential for future robotics stuff.

-Mike