Verified by electronics

Forgive me, dear users, but for starters a small disclaimer:

Despite the "promising" tag, things like unboxing, followed by disassembling and demonstrating the inside of a quadrocopter assembled on an Arduino tube and printed on a 3D printer under the control of a 30-line script, unfortunately, will not be in this post.

The post describes the history of the search for the most acceptable way to implement the ideas of a person who desired a strange one, namely, he decided to cross his smartphone and car, and therefore had to spend some time creating his own collective farm original version of a car holder for a smartphone, at the same time and find an unexpected use of things intended, it would seem, quite for the other. Unfortunately, the idea of ​​capturing in the recent past in all its glory, well, or at least in the photo this perverted process somehow did not occur to me (the laurels of Tinto Brass left me indifferent, besides, to be honest, I was not sure in that from this idea something will come out at all). Anyway, to whom it seemed interesting, I ask for a cat.

Long and tedious prelude. Or the story of an unsuccessful struggle for freedom from wires

The desire to use the smartphone to listen to music in the car and the subsequent search for a way to realize this arose in me for several reasons. There is no love for riding in silence (it seems that it still stretches from the “happy” times of using the very elderly children of the domestic and not only the automotive industry and the permanent state of doomed readiness associated with it at any moment to hear the completely spoiling the mood of something times dying in the womb of hellish mechanism). And a very cool attitude to listening to the radio at rush hour with its endless news, “hello” programs, tons of advertising and other conversational genres. And also the complete lack of desire to mess with CDs (they and only they were allowed to use the standard audio system of my recently acquired car of that time). The prospect of regularly rewriting a whole heap of CDs for “synchronizing” a constantly updated music library, which I already kept on my smartphone, followed by the need to carry them and even change it on the move did not inspire.
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“This is some kind of Paleolithic!” - I thought, and, recalling my rather successful experience of using a smartphone with a Bluetooth headset during walking, I hoped to connect my smartphone with a car audio system without wires. After her cursory study, the latter said its decisive “no” , but unobtrusively hinted with a huge button for selecting a sound source with the “AUX” inscription on the front panel that it had an external signal input. By simple "googling" and careful abuse of the car's interior, the coveted entrance was found in the form of four unused pin'ov connector on the rear panel of the audio system, resembling the connectors on the motherboard to connect the power buttons, reset, LEDs and other things. Quite quickly, an inexpensive and unpretentious stereo Bluetooth headset was acquired. A little fiddling with the manufacture of the cord connecting the audio output of the headset to the audio system input, during which the victim of the depravity described by the accuracy of the “factory” soldering of the headset and the turned-on cable for connecting additional USB connectors (I went to making audio mate audio part of the audio connector), I tried This is an improvised miracle of wireless technology.

Surprisingly, it worked well, and I finally heard the long-awaited beeps from the car ’s speakers . But the joy did not last long. The headset, in virginity, being essentially a wireless headset, required charging its own batteries or any other organization for its power supply, and it was here that the pig lay. The creation of a charger working from the “on-board” power supply of the car did not pose any particular problems (in any case for me, because a much more knowledgeable person was involved in this). The problem lay in the fact that when you turned on this power, in the headset (and maybe in the whole bundle of headset-lanyard-audio system-car) there were interferences that kill the sound quality completely, even from my far from audiophile point of view. The improvement of this whole orgy with the introduction of “galvanic isolation” (whatever that means), various filters and experiments to increase the noise immunity of the cable, greatly improved the sound quality, but still the noise remained. At the same time, their character was sometimes quite clearly “threads” unknown to me, sometimes with the engine operation, even with the operation of the climate control flaps, which, when the ignition key is turned, are actuated by electric drives to a certain position. It became quite obvious that the headset normally did not want to work without significant improvements and a complete replacement that was brewing by that time (I really didn’t want to think about it). In other words, Plug and Play did not work, alas. On top of that, another much more significant drawback of unfortunate ideas was revealed. In the course of a mental experiment, it turned out that when listening to music, even behind the wheel, sometimes it would not be bad to switch tracks (who would have thought!). It was possible to do this exclusively, having previously taken out a smartphone from a pocket. As a result, neither an acceptable sound quality, nor the notorious usability, but instead, on the horizon, the prospect was quite difficult for such a trivial task of the proceedings with the electric part of the headset, the car audio system, and maybe the car itself. The idea cracked at the seams and begged in the trash.

Anatomy. Or how I got to the docking stations

Having distracted from the next unsuccessful searches on the Internet for solving these “daunting” problems, I noticed a smartphone on my desk next to my computer (suddenly). It was the first and only then-generation iPhone, bought, by the way, practically “from under the floor” (it’s even funny to remember, but in those troubled times “it wasn’t so easy to take and buy an iPhone”) although this is another story. The main thing is that a fairly convenient docking station was attached to it absolutely free of charge (unfortunately, Apple has eradicated this corrupting practice in subsequent generations). It was in her that he stood on the table, and, in fact, I paid my close attention to her. The fact is that in addition to the two 30-pin connectors (the “dad” for connecting the smartphone itself and the “mother” for the USB cable), there was also a 3.5 mm TRS-connector (in the mini-jack world) with an unequivocal inscription "Line out". Having removed the headset from the car in order to use its lanyard to rework it under the docking station, as a result of which, old headphones due to having the necessary connector became another victim of debauchery, I put a new design in the car’s cabin, consisting of a smartphone, a docking station and audio cable connected to the audio system. Looking forward to the next epic fail, I decided to try a very tempting feature - the combination of the smartphone’s connection to the car’s audio system, which is still vaguely presented by me and simultaneously charging it. For this purpose, I took the USB cable with me into the car and the car charging acquired “on the occasion” lying around.

Not only was the sound quality at a very decent level (in principle, at the maximum available to the audio system), moreover, it did not deteriorate at all when charging was turned on (no “compatibility” problems were observed), and most importantly, as a result, I was born “Crazy” thought - without inventing anything more, leave everything as it is with this desktop and docking station that does not inspire confidence to me.

To this end, I, without delaying the matter indefinitely, decided to carry out "flight" tests of the docking station and check whether it is able to keep the smartphone on the move. I put it together with the smartphone on the only suitable horizontal surface in the cabin - the “shelf” on the top of the dashboard near the windshield, and, holding my “new solution” with my hand, I went to look for bumps and potholes. For obvious reasons, I didn’t have to search for a long time, and soon I was surprised to find that the docking station not only holds the smartphone perfectly, even at “exorbitant angles of attack”, at which you would rather worry about the car rather than being able to listen to music, but also with the smartphone turned into a carriage a universal head unit for a car audio system, which is a very convenient player, as well as a sort of small similarity to CarPC. Well, in any case, it was possible, for example, to open any map on the Net and lay a route, even if using only the Sun, stars, traffic lights and other landmarks (due to the lack of GPS on the “breakthrough Internet communicator” I didn’t have a replacement for the car navigator at that time). At the same time, thanks to the extremely successful design of the docking station, putting on and taking off the smartphone from it did not cause any trouble. For this, Joni , accept my sincere appreciation. Of course, if you read Habr (no, well, what if!).

The “secret” of this combination of ease of use and the ability to reliably hold the smartphone that struck me was in an extremely simple and, in my opinion, elegant technical solution - the geometry of the recess in the “monolithic” case of the docking station, into which the device is inserted, with minimal gaps that prevent large backlash, repeats the geometry of its body, at the same time holding it and acting as guides for precise docking of connectors.

Believing in the approaching final torment, I quickly assembled it all in the car’s interior, carefully screwing the docking station to the plastic of the dashboard, putting the cables in its internal space, and connecting the fuse box to the glove box and securing the charger there, and began to rejoice.

I was happy, I must say, this time long enough. But as time went on, the trees became small, and the cellular networks improved. At a certain point, having decided that it was even uncomfortable to continue to stay with the completely outdated EDGE and without GPS, and “relying on me according to the law premium” I updated my iPhone to a fresh one at that time - the 4th version (“Latest model! ") And continued to rejoice, anticipating that now I will also have a car navigator, and the number of devices will not increase (well, I don’t like extra devices ). Now I had to rejoice exactly until the moment when, with the usual movement of my hand, I tried to install my new “head unit” to the old docking station. Despite the fact that it was designed for a completely different form of the device, a more “square” rookie still got into it. But the former “magic” disappeared - the new smartphone was frankly dangling in a clearly-deepening docking station and dangerously warped, striving to fall out of it, breaking the connector to which it also “got” when installing and only on which he seemed to hold on to. Not really upset even by the fact that there would be no freebie in the form of a corresponding docking station attached to a new smartphone, I was going to buy it, naively believing that this annoying trouble would be eliminated, so to speak, with a little blood by a quick and easy replacement. Only a trifle stopped me - at that time these newest docking stations did not exist in nature, and in the expanses visible to me this existence was not supposed even in the near future. Apple continued to surprise and this time unpleasant. We had to come up with something.

Having considered the options available for universal car holders, I noted a number of shortcomings in them that questioned the expediency of their use in this particular case of mine. For example, they had the necessary 30-pin connector, but there was not even a hint of any kind of linear output. He would have to organize it himself, and given the presence at the end of the cord of such holders only a cigarette lighter plug, this threatened to turn into the manufacture of a new cable with attendant abuse of the holder’s design, which was usually embedded 30-pin connector with a coveted linear output on which then from his contacts (after the prescription of years I don’t remember exactly, but then I didn’t even find his pinouts). I considered the constructions from a simple mechanical holder and separate cable to be a complete heresy from the point of view of ease of use (I was not bothered by the successful experience with the docking station, compared to which using all these snaps and hooks looked difficult and depressing). In addition, the main disadvantage for me and my car was almost all of these holders was their method of attachment - on a suction cup to glass or another smooth surface (I just couldn’t find a single seat in the cabin where I could fix it without closing myself a review or not being able to interact with a smartphone without complicated gymnastic exercises). I wanted the strawberry amenities and I decided to make my own car holder, devoid of all these disadvantages and satisfying me 100%.

Actually action

Having disassembled the existing docking station and took out a small board with a soldered connector on it and getting rid of the cargo present there, I decided that it would be easiest to use this small board in some basis of my future holder, and secretly carry the cables from the existing connectors through the design bracket, which did not exist even in my fantasies.

Leaving for the time the hard thoughts about how to make the bracket and the base of the holder, I began to search for the place to install it in the car. The most optimal seemed to be the place where the left vent deflector on the central “console” of the dashboard was located - to the right of the steering wheel, not too high or too low, right at hand.

At first, I even intended to somehow use this deflector for fastening the holder, including passing elements of the future arm with wires through its holes and subsequently fix them securely to the power elements of the body already in the inner space of the dashboard (then the whole structure seemed rather heavy to me and with a big shoulder), but refused this undertaking, because I didn’t want to spoil the original plastic elements of the interior too much. Under the deflector there was a removable block of buttons with a corresponding hole, which fit even better than the holes of the deflector. It turned out that despite the mirror symmetry of all this “non-Euclidean” geometry of the plastic lining of the central “console” (in the photo above is a gray element that includes a horizontal shelf, ventilation deflectors, buttons and frame of the car radio), the button block could be swapped with a strange stub. By the way, the purpose of this thing for me for a long time remained a mystery (however, as I found out in the process of searching for illustrations for this post, not only for me it was a mystery ). Only by pulling it out of my nest, I realized that it was a kind of coin box (so European designers decided to add functionality to an elementary stub), and not some kind of thermometer, sensor or microphone of the Handsfree system for more expensive bundles, as I thought earlier. I decided to sacrifice this useless piece of plastic for me.

Having decided on the future location of the smartphone, I wondered: why would I even need to build a complex bracket, especially since it would be more convenient for the smartphone to be located as close as possible to the surface of the dashboard? Wouldn't it be easier to somehow fix the docking station board directly on this very coin box, turning it into the only, and most importantly already ready, element for fastening the holder body to the dashboard? It remained only to think of how to combine all this into a monolithic case, which, if possible, would also have the “magic” of the docking station, that is, it would have a recess around the connector that repeats the shape of a smartphone.

Epoxy! Collect all that I had, make a form that defines the external surface of the holder and fill it all with "epoxy" (to hell! In fact, how much is possible?)! It would have turned out to be a solid and durable "plastic" construction, which is easy to process and bring to a completely acceptable appearance. My indescribable exultation was overshadowed only by the prospect of the complex production of this very form. It would be necessary to make a kind of "trough", on the one hand limited by the overlay of the dashboard's central "console" (otherwise it would have to be an ugly and complicated transition from its surface to the holder's volume due to the fact that it turned out to be wider than a coin box) the other side, in which another form would be immersed, which is a kind of “cast” of the smartphone. In this case, it would be necessary to ensure the integrity of all this horror, and especially in the place where the smartphone is connected to the connector, which was supposed to protrude from the solidified "epoxy" array.

"Epoxy", "trough", "casts" - it was like a nonsense. From all this geometry (which, by the way, is not only difficult to describe like this, “on the fingers”, but I suppose that the pictures from the video here would not really help) boiled over the brain and no longer wanted any music. How, for example, to make this "cast of the smartphone"? Do not drown the smartphone in epoxy resin. The idea was not worth it. It was necessary to stick around the smartphone with something like plasticine and pour the resulting form with something like plaster. Thoughts about "epoxy" and plasticine strangely mixed in my sick imagination and turned into ... "cold welding", or rather "plastic epoxy composition Epoxyline." As it turned out, a very popular thing in the hands of fornication Delia.

“Easy to use”! "After curing, you can polish, drill, paint"! This is what I need! Always wanted to polish, drill and paint after curing! A second wave of jubilance swept over me. I vividly imagined how I would break the front part of the coin box, turning it from a certain similarity of a rectangular glass into a rectangular similarity of a tube, saw through the grooves in its side walls in order to insert and fix the docking board, connect the cables and, sticking a smartphone I will bury it all in a single array, which then will only have to be given a complete shape in places and voila.

Once again, the jubilation was interrupted (this is no longer funny). This time I faced the problem of how to painlessly stick a smartphone with this very "tenacious" epoxy compound (after all, it is intended for gluing all types of metal, plastic and glass, that is, for gluing my smartphone to anything). I needed to somehow protect him. To this end, I decided to wrap the smartphone in a plastic bag, and then coat it with some kind of release agent. The idea failed due to the fact that, firstly, polyethylene created a large number of fairly large folds on the surface of the smartphone (they would certainly have printed on the form), and secondly, it just burst when trying to “plant” the smartphone packaged in this way. I needed something that could greatly stretch, just making it easier for the device and the dock board connector, and at the same time have sufficient tensile strength. It did not take long to think.

Having collected everything needed to make my original car holder for the dash of the docking station, I finally and by that time already somewhat reluctantly convinced of what I actually do, “light hand movement” pulled a condom on my smartphone and stuck it in . To my own surprise, I did not even say anything like “Hehe,” noted that even… “pimple” at the end of the rubber product (dear Habr, I must admit that when writing this post, even honestly tried to find on the Internet more, perhaps, a technical term for this part of the used device, but, alas, did not find it). This bulge turned into a recess embedded in the smartphone connector, reduced the tension in this part of the pairing of the smartphone and the docking station board (in these terms it is really not easy to describe) and at the same time completely eliminated even the slightest possibility of folds that would spoil the shape . “It sits like a glove” - I concluded, and, having kicked out a few air bubbles from the place of the future contact of the smartphone with the docking station, I started to fill with “Epoxy”, a previously prepared and processed plastic coin box with the board. After finishing with this fastening element, I inserted it into the lining of the dashboard's central “console”, which had been removed from the car, and this time, chuckling idiotically, smeared grease residues from the condom packaging with the surface of this lining around the supposed docking station so that later need to be able to remove it painlessly. Then, aligning the smartphone with respect to the lining, stuck out the part of the board with the connector and the bottom part of the smartphone that was sticking out of the already insigned coin box and left all this disgrace to harden.

“After curing,” I hurried to disassemble the entire structure, easily pulling out my smartphone and finding a perfectly smooth inner surface of the indentation with an unharmed connector at the bottom, which exactly followed the shape of the smartphone (even a small dent repeated on its bottom, a consequence of a fall) and perfectly fixed it . The dimple itself was located in a shapeless lump of very durable plastic, at the other end of which was the untouched case of the former dummy coin box, which with a characteristic click was securely fixed in the above-mentioned dashboard element of the car, almost without a gap, docking it with a dash dash station (the case was fixed even better than before, apparently due to the fact that it was slightly wedged as a result of dense stuffing with this “plastic epoxy compound” and from what I was trying to yaky case, to improve the "adhesion" in its pre nasverlil openings walls). To be honest, I was pleased with the result (up to this point, I thought that the docking station would most likely be buried in the depths of epoxy and that would be the end of it). The case remained for small.

This is the end!

This “small” I hurried to do. Wiping the smartphone and everything else from the omnipresent grease, I returned everything withdrawn earlier in the car and turned it on. Surprisingly, everything worked perfectly (Epoxyline really turned out to be a good dielectric). Having disconnected the almost ready holder, I began to give it a “presentation”. I decided not to bother with the design and tear it off from Apple (come on, Joni ), trying to make the most of the original docking station’s shapes, especially since it was very convenient for such a repetition (essentially a parallelepiped with one “beveled” edge and rounded vertical ribs). Sawing and sandpaper and file processing this material turned out to be very simple. At the same time, the surface turned out to be quite smooth, and after “polishing” with a simple cloth, it acquired luster. The only thing I did not dare to do was try to paint it normally. I decided that putting any enamel on the surface would not work well enough for me and my smartphone would “wipe” it in use, and the paint could have been unacceptably reduced the already small gap between the surfaces. Anyway, I frankly fooled - I took an ordinary permanent black marker and “painted” the surface in this way. It turned out, to put it mildly, “not very”, since color irregularities were visible close to (no matter how hard I tried, but the material absorbed the dye composition and the felt-tip effect on paper was obtained, moreover, the small granules of the filler present in "Epoxy"). It also revealed the smallest surface defects that I had not noticed before painting and which, I believe, could have been removed with normal painting.Nevertheless, I didn’t redo anything, especially since from the normal distance the hack didn’t look so awful and didn’t even catch my eye. On the only photo taken you can estimate the result of the whole working day.

As for convenience and functionality, the device served me without any complaints for several years and, being in good health, together with the car and the smartphone passed safely to the current owner.

In conclusion, I would like to say that I understand perfectly well that most likely I then invented the next “bicycle” and much could have been done differently and better, including regarding the writing of this post. I think spring comments will show where I was right or wrong (and who am I after all that I did). Anyway, I give my “revelations” to the court of the respected Habrasoobschestva and ask only that they do not judge me harshly.

In the end, I was young and I needed a car holder for a smartphone.