Winchester speaker



    Greetings to all habroyuzer. Today I’ll tell you how I suffered from garbage , I was engaged in almost selfless occupation, namely, I turned an old non-working hard drive into an almost full-fledged speaker.

    I also made a video that completely duplicates this article, here is its first part:



    And here is the second one:



    The inspiration for the creation of this article is a companion publication Kidar - If Seagate dusty ... .

    So, to create such a "creative" we need:



    • A non-working hard drive, in principle, any 2.5 or 3.5 inch will do;
    • A4 sheet;
    • Scotch tape, or instead you can take glue for paper, for example - PVA ;
    • Plasticine, well, or chewing gum;
    • Soldering iron;
    • "Crocodile";
    • Multimeter;
    • AA or AAA battery or rechargeable battery (finger / mini finger);
    • A low-power amplifier for a couple of watts, for example from old speakers, or bought like mine;
    • Hexagon screwdriver (see photo below);
    • Postings.


    The first thing we need is to unscrew the board and the top cover of the hard drive, if it was working, then after opening it will definitely be khan.



    Screws, as a rule, have hard drives with an internal hexagon.



    Be careful, as a rule, one more screw is hidden under the label of the top cover, so if the top cover does not disassemble, look for where you missed it.
    After removing the cover, we will see something like this:



    Almost any hard disk has a similar design - a rotating disk that rotates using a brushless motor, such as aircraft modelers use, only it is very weak, literally a couple of watts, the quadcopter will not take off with this configuration100%. There is also a read head, which, as it were, “hovers” over this disk when it rotates. The head is set in motion by a combination of an electromagnet and a permanent magnet, by the way, as a rule, neodymium magnets , which are very powerful for their sizes , are in hard disks . There is also a “limiter” of the head stroke (yellow little thing behind the magnet) so that it does not go beyond the edge of the working area, and so, it will not allow us to remove the disk from the engine, so it needs to be either unscrewed or broken in another way:



    Inside of this plastic, the same neodymium magnet is used as the mechanism for parking the head at the initial position, only a small one, the size of a match head, I think that these are just perfect for projects on reed switches orHall sensors .



    We unscrew the screws that hold the disk, move the head to the side and remove the “damn”.



    Since the engine must rotate at high frequency and for a long time, it also has a hydrodynamic bearing .



    This is what the read head looks like.



    By the principle of its operation, it is similar to the principle of operation of the head as in a cassette or reel player.

    Well, we’re finishing the “hard” reverse engineering, now we need to find the coil contacts on the connector that connects the Winchester’s Hermoblock and the board to the electronics, now a device that can measure resistance will not interfere.



    The coil resistance should be in the range from 4 to 40 Ohms , in my case about 11.



    As practice shows, the coil contacts are opposite each other, in mine it happens on the top right, but with the previous alteration of the old 20 gigabyte hard drive, the coil was on the bottom left, so if I have this, then you can have it differently, for this I have included a multimeter in the list of what is necessary. The technical matter is further:



    Now we need a battery to make sure that the wires are soldered to the right place, take the battery and connect one wire of the coil to the plus of the other to the minus and the head should turn to the side, then we change the polarity and the coil should turn this time to another, if everything as I described then everything was done correctly (see the first video at 13:16 ), if not, most likely, they didn’t solder to the coil.



    A few words about how a regular speaker works.- there is a magnet that has a south pole (indicated by the letter "S" in the figure above) and a north pole (indicated by the letter "N") and there is an electromagnet that also has poles, only in contrast to the polarity of the power source they can be interchanged, moreover changing the current that flows through the coil, we change the power of the electromagnetic field.
    Magnets have one interesting property, either attracted or repelled when interacting with each other. If the pole of one magnet, for example, is the south, and the other is the north, then they will be attracted, if the poles of the two magnets coincide, they will repel, if you want to learn more about this then visit the Wikipedia page for magnetism .
    The usual speaker works in accordance with the same principle in our speakers, as if “pushing” air, creating sound.
    We know that the larger the speaker in a subwoofer, the more powerful the sound is, right? In order to amplify the sound, the speaker design still has a diffuser, which is designed to “push” as much air as possible, creating a stronger, and therefore louder sound. The speaker also consists of a lot of things, but in the context of this article I’ll probably finish, so as not to drag out this long article, here is the Wikipedia page on the electrodynamic loudspeaker where you can read in more detail about how the speaker is arranged, which we have in the columns.

    Now, in principle, you can send a signal from the amplifier to the head, but it will sound very quiet, to avoid this, we need to make the simplest amplifier, in my case from sheet A4:



    Here is a cone, the larger the radius of its base, the louder our "speaker" will sound. In order to keep everything I glued with tape, you can use glue instead of tape.



    Then we press the top of the cone “crocodile” as close as possible to the reading head. Personally, I didn’t come up with anything better, if you have any ideas - write in the comments.



    Then we need to make such a holder here from plasticine / chewing gum for a cone, only we first need to wait until the plasticine or chewing gum hardens.



    Its function is not only to hold the cone so that it does not go around, but it will also add a little low frequencies, no matter how wild it sounds.

    Now it’s already possible to send a signal from the amplifier to the head and lo and behold, it plays, the sound quality is certainly not like that of a Hi-Fi system, but it doesn’t differ much from the sound of inexpensive Chinese speakers.
    But that’s not all, it sometimes happens that the mechanism for parking the head to the initial position is a little different than in my case, it happens that it is not removable or difficult to remove, and it is designed so that the head sticks to it, and then it turns out generally disgusting sound.
    I decided for myself it is very simple: I



    just made a kind of “side” that prevents the head from sticking to the starting position.



    By the way, I have a stereo amplifier, a 2x3W D-class based on PAM8403, the size of a coin, at the moment it is one of the cheapest stereo D-class amplifiers, a great little thing for the money.

    And here is my home-made stereo system:



    Sound test closer to the end of the second part of the video.

    A couple of words on the topic “Why?”, “What is the point?”, “Isn’t it easier to go to the store and buy a normal one?” And so on - I don’t see much point in it, just a way to somehow entertain yourself, if at hand there is everything you need, but nothing to do, for the sake of fun for fun.

    Links:

    If Seagate is dusty ... ;

    All my publications .

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