Hard disk speakers
After discovering that I had a few dead hard disks lying around I decided to take inspiration from AfroTech and make some cool hard disk speakers. I discovered a couple of new things, too.
The essence of this HD speaker idea is that hard disks contain a movable coil in a magnetic field that is used to move the heads from track to track on the disk. A speaker is also a movable coil in a magnetic field, hence if you can find a way to feed an amplified audio signal through the coil in a hard disk, you should get sound. And the point, you might ask? Well, there isn’t one, but what else can you do with a dead hard disk? (besides make a nice shiny mirror out of the platters, anyway).
Equipment
- One (or more) dead hard disks (if they’re not dead, they will be soon).
- Various little screwdrivers to take the drive apart.
- An amplifier. I advise you don’t use your favourite stereo in case something goes wrong, though I did and it didn’t.
- Some wire. Speaker wire would be a good choice.
- A paperclip (metal, not plastic-coated).
- A soldering iron and some solder.
- Pliers.
- Some music to play on your new creation when it’s finished.
Method
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Take your dead drive. Mine was a Quantum Fireball, which seems a rather unfortunte choice of name for a hard disk. I accidently killed it in a very non-fireball-like manner during an incident involving static. Capacity is (was) a whopping 4GB. It actually had Linux on it, so I suppose it’s kind of an open-source speaker now.
The Quantum Fireball EX 4GB, a behemoth of data-storage technology.
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Remove the screws holding the top cover on and prise it off. As well as the ones around the edge, there were some under the ‘warranty void if removed’ seals. I have a feeling that this drive wouldn’t have been under warranty now, anyway. You may well find that some of the screws have Torx heads, so go hunting round for that set of Torx bits you know you have somewhere just for this eventuality. There was also a seperate little metal cover to remove over the ribbon cable that connects the inside of the drive to the PCB on the outside.
Torx screws. Ugh.
Victory is mine! Oooh, shiny…
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Have a look near the coil for somewhere that you could solder to. In this case, there’s some contacts next to the heads, but they in turn connect to the ribbon cable which runs out of the drive and connects to the controller board on the bottom. It’s therefore possible (not to mention easier) to solder to the contacts at the end of ribbon cable, some distance from the coil itself.
The coil contacts and the ribbon cable which carries power to them.
The underside of the drive, showing the controller PCB.
This is the other end of the ribbon cable.
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Pull the ribbon cable out of its socket on the board, and remove the PCB which is secured by a few more screws.
The bottom of the drive with the controller board removed. The contacts in the middle are for the spindle motor, but I couldn’t get it to work.
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Follow the tracks from the coil contacts back along the ribbon cable to the other end. Rather than solder wire directly to these tiny little contacts I found it easier to solder a bit of paperclip on first and then connect the wire to that. Make sure there’s no solder bridging the gap between the contacts—your amp really won’t like a short circuit!
Bits of paper clip soldered to the appropriate contacts on the ribbon cable. Excuse the crap soldering—my soldering iron has an enormous bit and the contacts are tiny. And I’m crap at soldering. Bridging the other contacts with solder doesn’t matter (they’re only for data, and it’s not like we care about that any more), but really make sure you haven’t bridged the two coil contacts. Scratch the area between them with something sharp to remove any solder that’s there.
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Almost there now. Connect your speaker wire to the two bits of paperclip (it doesn’t matter about the polarity), and the other ends to your amplifier.
The speaker wire soldered to the the other ends of the paperclip bits.
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Cross your fingers, and switch on. Something with a lot of bass is good to get the heads moving nicely. Hopefully you’ll hear something.
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Mine worked first time, but I noticed the heads weren’t moving much. I took the magnet off the top of the coil to have a closer look (they’re very strong), and discovered a plastic widget which locks the heads in place, probably to prevent them moving when the power’s off. With it removed and the coil reassembled things worked much better.
How to remove the magnet from the top of the coil. It’s pretty strong—watch your fingers.
Pull out this piece of plastic which locks the heads in place.
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Finally, I noticed that the drive was making a nasty rattling sound when the heads hit the stop at the limit of their travel. A strip of foam cut from a sheet that was under the PCB shoved in the right place stopped that.
Putting a small piece of foam between the coil and the stop quietens any annoying rattles.
Results
See for yourself. Note the sound quality is better in real life than in the video, becuase my digital camera microphone isn’t exactly great.
DivX5 encoded AVI, 32 sec, 2.06MB
I’m pretty impressed with it actually—it sounds at almost as good as a little transistor radio, just a bit more rattly. I found that you get a noticable improvement in sound quality if you screw the top back on to create an enclosed space for the sound to reverberate, but it doesn’t look half as cool if you do that.
Screwing the top cover back on improves the sound, but means you can’t see the heads moving. Perhaps I need to create a window&hellip
I put the little metal cover that protects the ribbon cable back on too.
Conclusion
Converting a defunct hard disk into a speaker is largely pointless but fun. It is the only speaker I own which has any data storage capacity though, which I suppose is a unique point.