Right guys, I've been roped into making a little display feature for a shop window which will have an opened hard drive spinning with the drive head randomly searching. So far i've got the stand and point of sale done, the drive is powered up, but after the initial head movement it just parks back into the off position. I'm sure I saw a mod on here where someone did something similiar with a knackered drive, but put it inside the clear case for visuals only. If anyone knows of this thread, or anything similiar, or any details of the circuit I would need to use, please post! Many thanks in advance P.S. The display is to advertise data recovery services
I knwo what you mean, i dont remember it on here, i saw it on some other site, but yeh, basically he dragged up all the scemas on the chips on the logic board and hot wired it all up so it would just seek to random places I'll have a look around
Well, it depends on what type of actuator it uses. If it's a really old drive, they used to use stepper motors, if it's fairly recent, they actually use voice coils (similar to speaker voice coils). If you have a voice coil that is a decent impedance, you could actually control it with an audio source, such as a stereo. You could play music on it, and that would be one way to get random movement... Ah, here's a project describing just that, only they even added lasers! http://hackedgadgets.com/2006/06/01/making-a-hard-drive-laser-oscilloscope/
Thanks for the info guys, am I right in thinking any modern drive will use a voice coil rather than a stepper motor? The drive thats getting the treatment is a 40GB seagate with some bad sectors. While using a stereo source would be a really fun idea i'd actually rather make a small ciruit that I can just 'set and go', but thanks for the read anyway geogecko Any luck finding that page dragon2309 ?
sorry wolf, no luck. It was on a page with about 20-ish other mods involving harddrives. Looked liek a really old page, and now i think of it, i think it was linked to from a post on here somewhere. I can't for the life of me think what it was called, sorry
Well, most likely, it is a voice coil. The way I see it, is you have a couple options. 1. Drive the voice coil directly, which would probably be the easiest. 2. Find out if there is a chip on-board that drives the voice coil, and see if there is a possibility of interfacing to it. This seems more difficult, as you will need to "disconnect" the I/O that is normally controlling that chip from somewhere else on-board. 3. Take part of 2, and add your own! If you can find out which IC is being used to drive the voice coil, and it's a relatively simple IC, and doesn't require much supporting hardware, you could build up your own circuit using the same IC, then just disconnect the flex circuit from the voice coil to IC interface on-board, and connect it up to your circuit instead... It seems like if you drove the voice coil directly, all you would need is some type of audio amplifier (possibly just a simple transistor amplifier, I'm not sure), then use a PWM pin on the PIC to generate the frequencies, to make the movement random. You may need a low pass filter on the output of the PWM from the PIC, to filter off the high frequency edges, but it may not be needed. It would be something you would have to play around with, as the power needed to drive the voice coil is kind of an unknown, and the frequencies to position information is also an unknown. It might be best to go ahead with a stereo source, and maybe one of those test CD's that has frequency tracks that you can play. Then you could measure the Vp-p of the signal going to the voice coil, and if you knew the impedance of the voice coil, you could get a general idea of how much power is needed to drive the it, and also get a feel for the frequencies you want to use... It's probably not a trivial project, if you can't just find a circuit that someone has already come up with...good luck, I'll be waiting for results!
I reckon you've got the best idea with the stereo source gecko, any ideas on what to use? obviously with it being just a small display it'd be kinda silly rigging it up to an old stereo or mp3 player, I was thinking about having a look round some of the old crap in the back for a small radio (those cheap £4 woolworths ones), if i can find one with a line out, or even mcguyver the speaker connection to it, I should also be able to rig it up to the same 5v psu with a few resistors, what you reckon ? Would mono work (as in the radio idea?)
Actually, mono would work, as you'll only have one voice coil. A line out may not be enough power to drive the voice coil though. I was thinking, high level outputs. In other words, it may need to be able to provide a few watts of power to the voice coil.
kewl, i'll give it a go tommorow when i've found a suitable radio, i'll just crank the volume till i get a response, whats the worst that could happen? it's a broken hard drive . . . And I have several suitable candidates to take it's place should it submit to a blue smokey death
The mod you are talking about is by ZapWizard - His site is www.zapwizard.com The mod you are talking about is here: http://www.zapwizard.com/Mods/RealHD-IDE/index.html
Of course it is! thanks for refreshing my memory! i've been typing all sorts of crap into google to find that page lol
One thing to remember is that an audio amp will have a high-pass filter at ~20 hz or so maybe higher for smallerspeakers... What kind of effect will you get from the HDD head? I'm not sure, it could vibrate in place untill bass hits (if your feeding it music) which could send it back and forth pretty quickly. you can definitely make it move, but you may, or may not be satisfied with what you get. See if you can find a midi keyboard program for your comp or something and play around with the notes and different instruments to see what you can come up with.
Interesting. It looks like if you can do what he did, you could use a PIC or something to send a PWM signal to the trip voltage, with a filtering capacitor (to smooth it out), and then you could randomly move it wherever you wanted. That way, you don't have to worry about having a stereo and an amplified signal.
What ever happened to old Zapwizard anyways? It seems like he disappeared. He used to be one of the biggest members here.
Afrotech is the magic Google word. Check 'hard drive speaker' for more variations, tips, videos, etc.
Ok gents, bit of an update, i've had a fiddle using a CD player and a little radio, but unfortunately the volume has to be cranked too high for there to be any sort of reasonable head movement, I'm gonna have aproper bash at zaps method tommorow to get the effect I need. (while the radio and cd methods work great, the music is simply too loud to be used as a display piece)
