Winchester speaker

Greetings to all habouriors. Today I will tell you how I suffered with garbage doing almost disinterested work, namely, turned the old non-working hard disk into a practically full-fledged speaker.

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



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

So, for the creation of such a "creative" we need:

• Non-working hard drive, suitable, in principle, any 2.5 or 3.5 inch;
• A4 sheet;
• Scotch tape, or you can take paper glue instead, for example, PVA ;
• Plasticine, well, or chewing gum;
• Soldering iron;
• Crocodile;
• Multimeter;
• A battery or rechargeable AA battery or AAA (finger / mini finger);
• 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 a worker, then after opening it will definitely be his khan.



Screws, as a rule, at winchesters with an internal hexagon.



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



Virtually any hard disk has a similar design - a rotating disk that rotates with a brushless motor, such as using model airplanes, only it is very weak, just a couple of watts, with this configuration, the quadcopter will not take off 100%. There is also a reading head, which seems to “float” over this disk when it rotates. The head is set in motion by the combination of an electromagnet and a permanent magnet, by the way, as a rule, neodymium magnets , which are very powerful for their size, stand in hard disks. There is also a “limiter” of the stroke of the head (the yellow thing behind the magnet) so that it does not go beyond the edge of the working area, so, it will not allow us to remove the disk from the engine, so it needs to either be unscrewed or broken there is another way:



Inside 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 believe that these are just perfect for projects on reed switches or Hall sensors .



Unscrew the screws that hold the disc, move the head to the side and remove the "pancake".



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



Here is the reading head.



By the principle of its work is similar to the principle of the head in a cassette or reel player.

Well, we are finishing the reverse engineering of “Hard”, now we need to find the coil contacts on the connector that connects the HDD of the hard drive and the board with the electronics, and now the device that can measure the 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 my case right above, but with the previous alteration of the old 20 GB hard drive, the coil was left below, so if I have this, then you can have another I have included a multimeter in the list of what is needed. Next thing technology:



And now we need a battery in order to make sure that the wiring is 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 move to the side, then change the polarity and the coil should move to another time Everything is as I described then everything was done correctly (see the first video at 13:16 ), if not - most likely, they were not soldered to the coil.



A few words about how a normal speaker works - there is a magnet that has a south (denoted 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 unlike the source polarity power supply they can change places, besides 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 they interact with each other. If the pole of one magnet, for example, is south, and the other - north, they will be attracted, if the poles of two magnets coincide - they will repel, if you want to know more about this, then visit the Wikipedia page for magnetism .
By the same principle, an ordinary speaker works in our speakers, as if “pushing” the air, creating sound.
We know that the more a speaker in a subwoofer the more powerful the sound, isn't it? In order to enhance the sound, there is still a diffuser in the speaker design, which is designed to “push” as much air as possible, creating as much as possible and, accordingly, louder sound. Another speaker consists of a lot of things, but in the context of this article I’ll probably finish, so as not to delay this so long article, here is a page in Wikipedia where you can read an electrodynamic speaker in more detail about how the speaker is, 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 a simple amplifier, in my case, from A4 sheet:



So this is a cone, the larger the radius of its base, the louder our “speaker” will sound. In order to keep everything I glued together with scotch tape, you can use glue instead of tape.



Then we press the top of the cone with a "crocodile" as close as possible to the reading head. Personally, I did not think of anything better, if you have any ideas - write in the comments.



Then we need to make here such a holder of clay / gum for the cone, just need to first wait until the clay or gum hardens.



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

Now you can already send a signal from the amplifier to the head and about a miracle, it plays, the sound quality is certainly not the same as that of the Hi-Fi system, but not much different from the sound of inexpensive Chinese speakers.
But this is not all, sometimes it happens that the mechanism for parking the head to its initial position is a little different 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:



Just made such a kind of "side", which does not allow the head to stick to the initial position.



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

And here is my homemade stereo system:



Sound test near 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 something normal?” And so on - I don’t see much point in this, just a way to keep myself busy, if you have everything you need at hand, but there is nothing to do, for the sake of lulz for fun.

References:

If Seagate was dusty ... ;

All my publications .