Home Made Multi-touch Displays, Media servers and stuff

Fixing a dead Hard Drive Hitachi HDT721010SLA360 (7200RPM 3.0 Gb/s)

2011-12-14T13:46:00.000Z

I thought I'd post this up here as it may help someone out - it certainly saved my bacon!

Picture the scene - you've got a 1TB hard drive thats full of important stuff, the next thing you know its dead!....

I had this happen to me - my home server (ie. spare machine that i just chucked stuff onto till I sorted something proper out) had become a bit of essential kit in the house. We had films, stuff for the kids you name it on there. So one day it stops responding so I reboot it - except the screen says there's no boot disk.... say what! - quickly take the case off, check all the cables, hell check everything and power up. Nope, its not happening - its gone - drive doesn't even spin up.

Words can't describe the feeling - but have a guess.

So I started to look around on the net for pointers - maybe this was an indentified issue, maybe I could "fix" this myself?. Hell I was desperate so was totally open to any ideas. Then I came across a site where they mentioned that quite often, as is the case with this particular model, the controller PCB on the underside of the drive is what's gone splat and so you can change it with an identical one and all will be well.

As sheer luck would have it - I'd actually bought 2 of these drives at the same time - identical model, but was only using 1 of them. So, quickly I removed the pcb from both units (you'll need a "hex" screwdriver - don't even "think" of trying something else - one wrong move and its bye bye pcb) and swapped them over. Take care with that "ribbon" cable you see below - those things break/rip/damage VERY easily.

A view of the PCB on the underside of the drive:

Power up and success! - the drive spins and a massive sigh of relief.

Except its not fixed.

Although the drive now powers up - its not doing much ( I had it plugged in using an external USB hard drive caddy thing - just saves time mounting/plugging/unplugging/unmounting it from the case) - no extra drive appears and the feeling of dread comes back.

So, quotes from mainstream "disaster recovery" places are well and truely off the menu. So I decided that my options were;

Accept the loss - like hell!
Try more extreme solutions...

Extreme - yep, like taking the hard drive platters out and putting them in a drive that I know works (ie. the spare one I had). I was ready to try anything.

I thought though, before I took a screwdriver to the drive - check google one more time.

And I found it - the answer. It seems that this drive stores the information about the way the disks in it are configured on a chip on the drive PCB. So simply swapping the boards over itsn't going to work - whilst I did solve the "power" problem that my drive obviously had, it didn't know how to then look at the disks inside it to work out where stuff was on them and thats why my drive still appeared to be dead.

So the solution is.... dead easy, simply unsolder the existing chip from the working PCB (which was now on my "dead" drive), and swap it with the same chip that was on the old PCB (that, in my case, had a power related problem). This chip, NVRAM as it's known is rather small and lets be honest here - SOLDER, ME? - last time I picked up a SOLDERING IRON was twenty years ago!

View the of the NVRAM chip on the drive PCB - its NOT the big diamond one in the centre - the NVRAM chip is that small square one underneath the large rectangular one.

It turns out that this process is pretty much what a full on DR company will do and from what I'd read - nothing else would work as this NVRAM chip was vital to the whole thing. Platter swaps, Drive heads you name it - none will work. All I needed to do was to swap the NVRAM chips over on the two PCB's.

Right.

Well, time to bite the bullet - no way could I afford to pay for it and as it turns out this make/model of drive has reliability issues, there's no way I'm going to use the spare one anyway so decision made.... I'm going in... With a hot iron....

So its tip time:

NEVER use a soldering iron that has a large tip - its got to be a small pointed one - you need precision here.
I worked on a basic golden rule - if I need to apply the iron to the chips pins for more than 1 second, I was doing it wrong and so needed to stop and wait a few mins to let things cool.
Another golden rule - your ENTIRE drive depends on this working - you'll get one shot at this and only one shot, mess this up and there is absolutely no way you'll get stuff back from the drive. SO TAKE YOUR TIME!
You do this entire process at your own risk - it worked for me, but if it doesn't for you then don't come complaining - I didn't hold a gun to your head did I?
Yep - ANY guarantee will be totally voided by this!
You'll need at the minimum - a soldering iron (obviously), some soldering wick and some spare solder.
Before you switch the iron on - clean it up, so it shines and if that means scraping/filing it with a knife etc then do it - its gotta be shiny. Having done this - when its heated up - "tin" the iron by putting some solder on it - this will get it ready for use - which should be shiny.
Get some sponge and make it wet - or wire wool - good for keeping the iron clean
If you have never soldered before - use google! - there's loads of sites out there that will show you the basics!
PRACTICE this process on something you don't want! - you'll only get one shot at this so don't go in blind!
Before you start - MARK the chip in some way so you know which way round it should be on the board - my picture should give you a good idea....

The NVRAM chip is what's called a "surface mounted" type - this means its "pins" don't actually go through the board - it simply sits on the surface and is "glued" to it using the solder. I started with the PCB that was on my dead drive (but which had the wrong NVRAM chip in it).

I wanted to only have the iron on the chip for the smallest amount of time possible. The chip is so small that realistically, you aren't going to be able to remove each pin one at a time. So what I did was to ADD a load of solder to the pins when I started as this basically joined them together. This meant that I could now heat up all the pins on one side in one go as the heat would transfer to all of them at the same time. So I used some pliers to apply a slight "pull" to the chip - put the iron in the middle of the pins and when the solder melted the whole of that side came up from the PCB in one go!

Repeat the process on the other side and hey presto - one detached NVRAM chip! - a little bit of minor bending of the pins and cleaning up with Solder Wick.

Now do this with the NVRAM chip we want to keep - you've done this process already so things should be simple this time round.

Just remember to take your time and also remember - CHIPS hate heat - so use it sparingly.

When you have both chips off, position the old NVRAM chip on the board that works and get some solder and iron action going on.

IT DOESN'T HAVE TO LOOK PRETTY - IT JUST HAS TO WORK!

Heres what I was left with after mine - not bad for someone who, as I said, hasn't touched an iron in 20 odd years!

Once you have done this - give it a few mins to cool down, then plug it in (probably using an external USB drive thing ideally) and if everything has gone according to plan - your drive will spin up, your computer will detect it and everything is good!

It was in my case.

2011-05-25T23:23:00.000+01:00

Wow, time flies doesn't it !

I realised just now that I'd not posted up here for ages - well Im not dead (though kids drive you to it sometimes believe me!). I think that my involvement with this project is pretty much dead now. I just don't have the the time - though perhaps when my son is older he can pick up the reins and make a multitouch display for a school project.

Still here!

2009-12-21T16:54:00.002Z

A lot has happened since my last post on this thing. Become a dad (again!), and moved house - only two things but damn, does time fly when you have a blue eyed monster to feed, and a house that needs totally gutting and starting again (bit by bit, room by room). I've not put this whole thing to bed - more on "hold" for the moment as I just don't have the time to put into it any more. What time I have is spent on my soon to be launched website - and even then, its few and far between!.

I'm actually thinking of binning the idea of using an LCD anyway. I've been "loosely" following the MT scene so I know that since it all first really "took off" people have made their own using LCD panels - so there's little point in me continuing that side of things (reinventing the wheel so to speak).

My plan is that when I get more time, I'm going to put together a proper MT table using a projector and front DI. I've had a play using WII Motes and damn! - it was so sodding easy I couldn't believe it! - there are issues with this technique in terms of the devices dropping the connection and them having restricted tracking but on the assumption these are ironed out, i'll probably use 2 or more WII Motes in the setup. I want it to be a kick ass table though - proper setup, leather trim, the whole works and to be hooked up to the house network so people can view pics, films whatever.

Part of me is really wishing the MS would release the Source software to the masses - though I can't see that happening for a long time yet.

Yay!

2007-08-29T21:29:00.000+01:00

The IR emitter turned up and oh man what a difference. The moment I powered it up it was like i'd just put the IR Sun in the room!

I'll definitely need some kind of IR diffuser as it was just too bright (28 IR LEDS) to shine straight at the sheet of acrylic (this was from underneath by the way). I managed to get a "diffused" effect of sorts by changing the angle but this meant I had a really bright "point of contact" that faded to nothing. It wasn't ideal but gave me a realistic testing area. The heavens opened - super bright blobs being detected all over place. After a good bit of tweaking on the camera I managed to get it to see just my finger tips - with the occaisional false blob (due to the position of my setup / test enviroment). It was more than enough to see it working properly for the first time with my fingers and not the remote control.

Naturally I fired up the Flickr photo app - oh man...

2007-08-27T20:12:00.000+01:00

Just a quick update.

I'm waiting for an IR emmitter to turn up. I think that there's so much ambient IR in the room that Front DI isn't working - or the webcam isn't up to the job (though I'm more inclinded to believe the latter).

Hopefully when this thing turns up I'll be able to try out Rear DI and see if I get any better results. If so, I'll look at mounting the LCD matrix on an acrylic sheet properly. I want to try and get the size down so this fisheye lens business may be the way to go as I think I should be able to mount the camera around 10cm or so from the panel - which means the whole "unit" should be fairly small and compact. I'd like to be able to "rotate" the screen, see-saw style around say 15%+- so i've been digging around on the net for something that might fit the bill -so far.... nothing. :(

2007-08-19T20:44:00.000+01:00

Have been doing some testing using a remote control and aiming it through the tft matrix at my camera. I already know this works but this is the first time I've had the sofware running as well watching the camera output to test how things perform......

A video to prove that you really can see IR light through an active tft matrix...

2007-08-16T23:00:00.000+01:00

A picture of the sheets that make up the LCD backlight.....

2007-08-16T11:46:00.000+01:00

Quick update. Been having a play with my camera - taken it apart (a Logitech Orbit one) and removed the IR filter - sandpaper on lens - not the best way but it seems ok - i've took some pictures of the process..

Once done, tried the cheap and cheerful, 3 strips of negative solution to block out all visible light. I actually cut the strips very small and then sandwiched between the sensor and the lens - works pretty well.

Then took a spare piece of acrylic I've got - only small, about 3 x 8 inches and started having a play with this thing they call Front DI.....

Stunned that it actually works! - there's lots of tweaking to do with the software though as it keeps picking up parts of my hand etc. I suspect that the best solution may be to provide additional IR light from a source either infront or the side. Dunno - need to spend time playing with it really I think.

2007-08-14T21:21:00.000+01:00

Have made my mind up - DI is definitely the way to go as the setup is far easier to tweak and play around with - and its far less expensive. The camera I've been using for testing looks like it probably isn't up to the job for a real prototype so I think I'll get a second one - the Philips one that people are mentioning on the Nuigroup site seems the best bet.

2007-08-13T22:58:00.001+01:00

Hmm - there's always a draw back isn't there.... Seems that "ficidual recognition" doesn't work with this method. Ficidual Recognition is (if I remember right) getting the system to see objects other than your hands and to know what they are.... not sure why this would be the case but hey, I'm new to this.

2007-08-13T22:51:00.000+01:00

Oh man this gets better. Seems the Diffused Illumination techique in my last post is really known as Rear DI. Effectively you are creating a beam of IR light and blasting out the box through the opening at the top. Your camera ( in the box ) looks for the light gathering (scattering?) where you are hands are on the acrylic and the software does the rest.

Now things get funky....

Role on the other type of DI - Front DI. This technique uses the natural ambient IR light that exists in the environment. This means that there's no need for any IR lights in the box at all..

So, my "list" of box items is.... a webcam (with filters etc), a backlight for the tft panel... and er.. that's it!. (it can't be this easy surely!)

Front DI is gonna get tested soon....

2007-08-12T23:27:00.000+01:00

Heh - looks like things just got even easier - seems that Diffused Illumination is the "new thing" in terms of Mulit-Touch and the best bit is its even easier. All you need is the acrylic sheet, your tft matrix, a camera, a "diffuser", a light (so you can actually see the tft!) and... an IR light source (you can either make this yourself or buy one - "IR Illuminator" on Ebay. Not sure of how exactly this stuff works, but work it does so plans have now changed a little....

Oh the fun to to be had.

2007-08-11T23:52:00.001+01:00

I've got some issues at the moment. In a knutshell I know that the acrylic sheet will be on top with the tft matrix underneath it, in terms of assembling this thing. The problem is that in order to see the display, I need to have some form of light illuminating it from behind. This could be a problem as I also need the webcam (currently an "Orbit" Logitech one) located behind the whole lot and pointing at the screen. If I put the light source behind the camera, you see a silouette of the camera behind the tft matrix. If I put the lightsource infront of the camera then there's a danger that the camera won't be able to see the matrix.

Another problem is the size of the thing. I don't want it to be a big chunky affair but rather something that is fairly slim ( I'm not expecting miracles though). From other setups I've seen most people have used a mirror - ie. the projector and camera are pointing at a mirror which is showing the back of the acrylic sheet - in effect halving the distance that you would need to locate them normally in order to get the same dimensions used.

So these two issues combined are presenting me with a problem - how to light the display, have the camera able to see the entire screen area and detect the "blobs", as well as not making the thing look god damn awful in the looks department.

Hmm...

2007-08-11T23:48:00.000+01:00

Have found a good place to get some of the electronics that are needed - which is actually very little. Essential the only purchases I need are the IR Led's to go around the acrylic sheet, some resistors for them and some form of power supply for the whole lot. I've seen some people who have used an old computer powersupply so there's various options. What I'm not sure yet is the maths invovled in terms of how many IR Led's I need, and therefore what kind of power requirements / resistors I should be looking at - need to do some swatting up on this I think.

Anyway, the place I'll be buying from looks like it will be www.farnell.com as they seem to have all the necessary bits (actually looks like there's pretty much everything you could ever want on their site!)

2007-08-09T22:25:00.001+01:00

As you may have guessed from the last post this entire project does involve taking a laptop apart. The funny thing is that anyone can do it - they're only held together by screws and for the most part - you won't be needing them again! (so no need to keep a track of where they all went - but its probably best if you try as you never know).

2007-08-09T16:18:00.000+01:00

A bit of background to wet your appetite...

The Acrylic sheet
The Acrylic sheet (this is the surface that you actually touch) has a bunch of IR-LED's around it's edges (lots and even more depending on how big the sheet is, roughly about 1.5cm apart appears to be the norm). Some people seem to use just two sides, others have gone right round the whole thing - it all depends I suppose on where you are using it (background "light"), the power of the LED's and the size of the Acrylic sheet. But how does this mean that the computer can see where you are touching?

FTIR
FT.. what!.... stands for Frustrated Total Internal Reflection. What's it mean ? - well in a knutshell, if you shine light inside through the edge of the acrylic sheet the light will bounce around inside the sheet like a rubber ball in a box. If you then touch the sheet the light "scatters" as they call it (or "gathers" as you would see it) where your finger is. This creates a big white "blob" - everything that touches the surface of the acrylic will create this effect to a greater or lesser extent. The multi-touchn setup uses IR (infrared) LED's so that your naked eye can't actually see this process - but your webcam can.....

Hows it all work then?
Well your webcam is pointing at the acrylic and therefore "sees" the white (IR appears like white light to the camera) light where you touch it. The computer thats connected then uses these touch points to work out where on the screen you are pointing and then moves something or does "something" on the screen. The screen is the interesting bit. The current setup as I said, involves you placing some form of sheet (i've seen tracing paper used) on the back of the acrylic (but not touching it) so that you can use a projector to shine the computer image onto the underside of the acrylic sheet. The problem is, hence this little blog, that the projector is damned expensive and the bulbs cost a fortune to buy. So.... is it possible to do this without the projector?

Yes.

What you need is a little lateral thinking. Laptop and TFT displays are perfect - find one that you don't need. An external display has the advantage of having long cables but a laptop also has everything you need, including the computer system to drive the whole lot. What you need to do is take the TFT panel apart, and by apart I mean COMPLETELY apart so that you are left with just the panel, no backlight etc - the whole thing should be a mere 1.5 to 2mm thick. It will still work fine except that without the backlight it is hard to see the screen. (actually its quite weird / cool to see the XP desktop sitting on a sheet of glass that so thin). Anyway, the overriding thing you need to be aware of is - take some care, then more care and then even more care when you take the TFT screen apart - the slightest twist or extra force will crack it = put it in the bin. The moment you stop caring about it, is the moment its dead - hold it and treat it like your life depended on it.

This is the panel - no really - the vertical plastic tube is one of my Harmon Kardon II speakers (its holding it up!) - the right hand edge of the speaker that looks white is actually the TFT matrix (you can see some pcb electronics curved round the speaker that lead from it).

Just to prove it - heres the front view. The white object behind it all is the backlight from the panel - you can see the ribbon cable linking the panel to the laptop between the two. For the curious, the laptop concerned is an old (but working) Toshiba Tecra 8200. You can get these for peanuts on Ebay, not literally - though I suppose you could if the guy selling really did want peanuts as payment ;)

Its kinda strange seeing the XP desktop on something that is only slightly thicker than your average birthday card.

2007-08-09T16:17:00.000+01:00

The current "accepted" setup for a multi-touch display involves a sheet of acrylic (ie. thick plastic) a computer with webcam (that can "see" infrared), a standard LCD projector and an array of IR-LED's mounted around the acrylic. There's some other bits as well but the point is that all this kit takes a bit of cash to spend and one item in particular (the projector) is pretty damn pricey to justify doing this at home.

So I'm hoping to have a bash at this multi-touch thing by using a laptop and a webcam instead of a pc / projector / webcam.... Can't be done?.... heh, well the experiments I've done to date say otherwise. True it's not "simple" but it is doable and if you've already got a laptop that works, but you don't need, or can get one off Ebay for less than a projector then your more than half way to making the thing. Most of this is in my head (hey that's the best place!) at the moment but I've done some experiments with some of the equipment required and so far they have proved 100% ok. All that's left is to tackle some of the other bits and then I'll post up how you do it.

The last "big" component that I need to work on is the Acrylic / IR Led setup. I've seen loads of other blogs / sites on the net from others who have done it so have a pretty good idea what I need and it looks like I can do it for around £50 (which is OK).

Welcome

2007-08-09T15:30:00.000+01:00

Hi,

Having recently seen the fuss thats started with Multi Touch Displays - ie. Microsoft's "Surface" table technology is based on this, I did some digging and discovered that its not a new technology but the concept has been around for years.

True some people are considered to be the experts in this (Jeff Han take note) but I thought that there's enough info out there now to start having a go on my own. With a difference.

Why do this?
Well, simply because its so uber cool that I've just got to have one! - and also, I think it would make a fantastic "toy" for my daughter and the rest of the family. Also, if I can refine the process, I may start developing and selling them to people - why spend £10K when you don't need to?.....

Check back soon.....