Musical Hard Drives

25,319

77

21

Introduction: Musical Hard Drives

If you love MacGiver you will love how I turned old hard drives into speakers for a Hi-fi system.

One of my favorite spot at work is the electronic dumpster, it's a great source for materials or spare parts.

During my last visit to the dumpster of wonders I found :

  • an old Hi-fi system but no speaker to go with it.
  • There was also a pile of old hard drives (busted or really old)
  • electric wires.

My first intention was to use those old hard drives to add real percussion capability to my Musical Floppy Drive system. But during my fiddling to find out what voltage was required to get the reading head arm to move all the way from one side to another I manage to get sound out of the HDD.

And then things got interesting.

(I apologize in advance for my bad English)

Supplies:

  1. Basic tools :
    • Flat, Philips and Torx head screwdrivers
    • Soldering iron
    • Multimeter
  2. For the simple demonstrator :
    • Hard drives (HDD), at least one for mono sound and two for stereo sound.SSD are not good for this project.
    • An audio cable with connectors that match your sound source (like mini jack earphones).
    • A sound source (mp3 player / phone / computer / Walkman / ...).
  3. Optional (if you are ready to go the extra steps and make it better) :
    • One or two plastic cups
    • Thin Electrical cables (~24 AWG like HDD's IDE cables) and 20 AWG (to connect to Hifi's speakers ports).
    • An audio amplifier or assimilate (hi-fi, car radio) if you want it to be loud and see the actuator arm move.
    • Wood planks or wood box to make a sound box.
    • Nails, hot glue.
    • Small screw terminals.
    • As many different kind of HDDs as you can find.

Teacher Notes

Teachers! Did you use this instructable in your classroom?
Add a Teacher Note to share how you incorporated it into your lesson.

Step 1: Video Proving It's Working

Now that I have your attention, let's continue.

Step 2: Similarities Between Speakers and HDD

Ok maybe this one is not that obvious : magnet and coil.

  • In a speaker you have a permanent magnet and a coil (impedance can be 4 / 6 / 8 / 16 / 32 Ohms).
  • In a HDD you have an actuator with permanent magnet and a coil (its impedance is around 7-11 Ohms).

So those two are really close electrically speaking.

For more informations check the Wiki page https://en.wikipedia.org/wiki/Hard_disk_drive

Let's go to the next step to do silly things.

Step 3: Identify Actuator Coil Pins

Identify coil's pins :

  • Open the hard drive by removing the top cover (optional, but it make everything easier).
  • Remove the electronic board under the HDD.
  • Find the actuator arm connector (that's the one with the most pins) and using the multi-meter (10 Ohm caliber or Beep) try to identify the 2 pins going to the coil (you are looking for 7-11 Ohms).

It's a bit difficult. If you can't find them try following the coils wires starting from the coil and going to the connector (It's the bigger tracks on the flexi-cable).

Time to attach everything together.

Step 4: First Demonstrator

Solder the audio cable :

Once you have identified coil's pins solder the audio cable to them (there is no polarity).

I used old earphone with a 3.5mm audio jack connector :

  • Cut speakers off
  • Strip the wires (on a stereo jack you have left audio, right audio and ground),
  • For mono sound connect right and left audio together and solder to one pin of the coil, solder ground to the other pin.
  • For stereo sound (you need two HDDs), Solder right audio to one pin of HDD1 coil and ground to HDD1 other pin. Solder left audio to one pin of HDD2 coil and ground to HDD2 other pin.

Time for testing :

Connect the jack 3.5 to an audio source (phone, computer, Walkman) and turn the volume up (all the way up !).

The sound is weak but audible (if you attach two HDDs in place of an headphone speakers you'll get a functional, and yet a bit impractical headphone).

You can improve easily the sound by :

  • Using IGMEC "I Get My Ears Closer"
  • Gluing a plastic cup the the arm (it will act as a flaring horn).

Want more ? I can help with that in the next steps.

Step 5: Now Let's Make It LOUDER

Ways to improve :

  • Find the right HDD that is loud and have the right pitch.
  • Keep actuator arm at a precise position.
  • More power from audio source.
  • Make a Loudspeaker by combining multiple HDDs together.
  • Add a sound box or speaker enclosure.

Step 6: Find the Right HDDs

Try to change some parameters :

  • Size : 2.5" or 3.5" or even 5,25" (be careful those ones tend to have a stepper motor in place of the actuator -> that's not good)
  • Manufacturers
  • Manufacturing time period : old 200Mb from the 90's to some 100Gb or 1Tb modern drives.
  • Technology : mono or multi platter, 5400 / 7200 / 10000 rpm.
  • Actuator arm that move freely or a more resistant one

It's up to you to assemble the HDD team that will fit your needs.

Some HDDs have a parking position for actuator's arm and a locking mechanism, you will need to disable it (refer to pictures to see some of those I came across).

Some HDDs were having their actuator arm hitting the magnet metallic casing and creating unwanted clatter. I glued small pieces of rubber in those spot to solve it.

Step 7: Actuator Arm Position

Actuator arm position influences the sound level :

  • The sound is louder when actuator arm is close to center or edge of the platter.
  • The sound is quieter when actuator arm is in between those positions.

You can fine tune different HDDs to works together at the same volume by adjusting the arm position and then using tape / glue / plastic bits to keep it there.

In my case I wanted to see actuators arms moving to the music. Music fidelity was not my goal, so they are free to move.

Step 8: Boost the Audio Source

  • You'll need to use an audio amplifier / Hi-fi / car radio with audio output impedance that match your HDDs. It's written next to the speakers output (standard values are 4 / 6 / 8 / 16 Ohms).
  • You need to have your speaker impedance that is equal or superior to the impedance written at the back of your audio amplifier if you don't want to overload (and eventually fry) it.

In my case I have 6 Ohms output impedance on the Hi-fi, so any HDD 6 Ohms and above is OK (not completely true, I'll go back to that shortly).

Step 9: Build a Loud-HDD-speaker

We will use the same process as the one for building regular loudspeaker.

We will need to connect ours HDDs in serial and / or parallel to have the an impedance that match to the one from the amplifier (it's not a perfect world, just try to get close to it or above).

  1. Let's start by getting impedance from both side
    • My HDDs impedance are between 8 and 12 Ohms depending on model.
    • My Hi-fi audio channels need to have 6 Ohms minimum (normalized value are 4 - 8 - 16 - 32 Ohms)
  2. A bit of Ohm law and I have the following possibilities (remember I need to be equal or superior to 6 Ohms) :
    • Two 12 Ohms HDD connected in parallel => 6 Ohms, Good
    • Two 8 Ohms HDD in serial -> 16 Ohms , Good
    • Two 8 Ohms HDD in serial -> 16 Ohms, in parallel with a 12 Ohms HDD => 6.86 Ohms, Good
    • ...

I used IDE-33 data cables (the ones that were with the HDDs) to make the leads for all HDDs (it's small enough to fit actuator pins and big enough to be manipulated easily).

To be able to change HDDs connections configuration toward each others I used screw terminal.

Note :

HDDs in parallel sound louder than HDDs in serial. So you have to listen to each of them and connect the loud ones preferably in serial and the quiet ones in parallel (if they have to work in the same loudspeaker). ==> At the same time don't forget to get the correct impedance. It's not an easy task.

Note 2 :

If like me you don't care about the Hi-fi (it's from the dumpster) just connect everything in parallel and make the Hi-fi suffer.

I ended up with two loudspeaker made of 3 HDDs connected in parallel and an impedance at 3.6 Ohms.

Step 10: Make a Sound Box / Speaker Enclosure

For the sound box :

a wood desk / wood box / metallic box will do the trick.

I built my own using a wood tablet, leftover particle boards and nails.

The size was determined by the thicker wood board (the smaller ones were easier to cut).

I put both channel on the same box because :

  • Not enough wood to make two
  • Not enough space for something bigger

If I had the time (and though about it back then) it would have been better to build the box in the shape of a flaring horn.

Step 11: Connect Everything Together

  • Loud-HDD-speaker left channel to Hi-fi (or audio amplifier / car radio) left channel.
  • Loud-HDD-speaker right channel to Hi-fi (or audio amplifier / car radio) right channel.
  • Hi-fi to music source (via Aux input)
  • Select a music to play

And Voila, done !

The sound is not so bad, I have real speakers (bought in shop) that are way worst.

Note :

actuator arms on my HDDs move more with bass line / drums or metal music.


Step 12: Want to Improve It Even More ?

Here some ideas (did not had the time or parts to try)

  • Make the platters spin :
    • Try reconnecting its motor to the electronic board and power it (not sure if it will work properly and you won't have any speed control).

    • Connect a hobby brushless motor controller to platter motor and a servo tester (or Arduino) to the brushless controller (start a slow speed to check for the correct direction).

  • Add some audio amplifier IC before each HDDs (like LM386 IC or 2N6292 transistor amplifier circuit) to get rid out of the Hi-fi or adjusting the volume of each HDDs separately.
  • Add audio filters to dedicate some HDDs to low or high frequencies.

Step 13: Some Test Songs

My microphone is not really good, it don't sound that bad in reality.

Reuse Contest

Runner Up in the
Reuse Contest

Be the First to Share

    Recommendations

    • Magnets Challenge

      Magnets Challenge
    • Snow Challenge

      Snow Challenge
    • Wearables Contest

      Wearables Contest

    21 Discussions

    0
    guiom31
    guiom31

    13 days ago

    J'approuve surtout pour le Hard Corner :D
    Bon boulot !

    0
    jedi1983
    jedi1983

    Reply 11 days ago

    Merci, je vois qu'on a les mêmes références.

    0
    anjoze
    anjoze

    13 days ago

    It would be realy amazing if you could make a VU meter with HD's
    Thanks for sharing

    VU_Meter.jpg
    1
    vanroeyrien
    vanroeyrien

    15 days ago

    Wow, this is genius! You got my vote!

    0
    jedi1983
    jedi1983

    Reply 14 days ago

    Thank you :)

    1
    sachit
    sachit

    15 days ago on Step 1

    Beautifully done. _/\_ I would love to make this project with couple of hard discs with yellow light illumination.Sound quality is nice. If we add two soft rubbers on both ends of the arm, may be sound of banging on the disc can be eliminated.

    I saw one project on instruct able where a rotating disc of hard disc are converted to display numbers at a location using position encoder. I guess we can make a alarm clock radio with rotating discs showing clock and arm producing audio.

    Thanks for the idea.

    0
    jedi1983
    jedi1983

    Reply 14 days ago

    That's an idea but the rotating disc might be a bit loud if you keep the standard 5200 / 7400 rpm.
    You will have to fine the sweet spot between minimum rpm for acceptable persistence of vision and quiet enough rpm noise.

    1
    ChrisA1
    ChrisA1

    15 days ago

    #4 "Hellion" by Judas Priest....nice pick!!!😀😀😀😀

    0
    jedi1983
    jedi1983

    Reply 14 days ago

    It was too tempting, I had to try it, and those little actuator arms did a great job on it.

    0
    Ravenobi
    Ravenobi

    15 days ago

    This is so BadA$$!!!! Might have to try this with my kids. Thanks!

    0
    prabbit237
    prabbit237

    Reply 14 days ago

    I don't think soldering wires to your kids and connecting them to an amp will work quite as well. Or then again, maybe it'll work *better.* Are they good singers? The power from the amp should at least get them to jumping some. If ya have both a boy and a girl, then you have your bass and tweeter right there.

    1
    shrydvd
    shrydvd

    15 days ago on Step 13

    Very cool! And, I don't know what you meant about your English . . . probably better than mine.

    0
    jedi1983
    jedi1983

    Reply 15 days ago

    Thanks a lot.

    2
    jessyratfink
    jessyratfink

    19 days ago

    That's fantastic! Thanks for including so many videos of it playing :D

    0
    jedi1983
    jedi1983

    Reply 15 days ago

    Thanks, videos is the best way to show the result for this project.

    1
    RuiF10
    RuiF10

    Question 15 days ago

    That's awesome! I'll definitely give it a shot!

    2
    Dennis R Levesque
    Dennis R Levesque

    15 days ago

    That was interesting. Had a lot of good info. I've tinkered with audio and computers, but not like that. Who knows what it can lead to.