A bit of "organic" * in the five-inch compartment

    Watching a stream of articles devoted to watches with vacuum indicators, I decided to share with you and my “invention”. But it’s not about the clock. It will be about a vacuum fluorescent indicator type ILT6-30M. And a device that does not perform any serious tasks (for now), but is simply a decorative element, such as a “mood lamp”.

    * warm, soft, lively, tube ... - well, organic matter!

    This indicator went to me along with the board on which it was installed. The whole design was a complete device for indicating the level of the recording / playback signal, which were used in the audio technology of the 80s. Turning this “thing” in my hands, I was sorry to take it apart, especially since there was nothing to stock it from. And it was decided to revive her. After the indicator blinked vigorously with two stripes, indescribably mysterious green, the search began - "where to cram it." But it never occurred to me. Everywhere he seemed superfluous or simply stupid. So he was lying on the shelf until the ACER CD-ROM was attached next to him. So the idea arose of “cramming” it into a standard case from a CD-ROM, and at the same time decorating a “boring box” under the table.



    This luminescent indicator has a size of 126x39 mm, and the landing indicator is even bigger! And experts in the genre already had suspicions ... - no, no ... I squeezed him in there. But for this I had to tinker. The first step is to remove the indicator lamp from the board. You need to do this very carefully and effortlessly, otherwise you can spoil the board and break the indicator conclusions. I used a vacuum syringe for sucking tin for these purposes.

    Further, all conclusions must be straightened out and done very accurately and accurately! None - "a little crooked." Further, the conclusions must be bent, strictly at the place of their appearance from the glass of the flask. The denser the pin is pressed against the glass of the flask, the better. Take this operation very carefully! To bend and bend will not work (well, if only once).



    The metal fastening band from the board must be removed completely. But the indicator will not be held on parole, the front (front) panel of the device will become a support and support for it. To do this, latches are glued onto it from the back side, into which the indicator lamp will be fixed. And the front panel itself, in turn, with a pair of other latches, will be attached to the metal case. A little inconvenient design for assembly ... - well, as it turned out.



    I made the front (front) panel from the standard plug of the five-inch compartment. The markup is shown in fig. 1.

    Now, the indicator and the board must be connected again. For this, I used a small strip of one-sided PCB, which also plays the role of a kind of distancer. This will be required when installing the board in the case. On a strip board, it is necessary, in some way (to etch, cut), perform the contact pads. The strip board must be glued to the main board.



    The inner surfaces of the metal casing must be glued with insulating material. The indicator lamp contacts will abut against the bottom panel of the housing. All back to back, but fits.



    When everything is ready, you can start the assembly.



    The indicator is set deliberately bulging, with all its smooth bends. And, of course, does not hide under tinted glass. All internal elements - grids, cathode filaments, anodes, should be available for viewing (well, it wasn’t me who invented ... such a genre).

    Electronic lamps, devices are mysterious and "gluttonous." They eat plentifully and varied. So, the display module, built on the indicator lamp ILT6-30M, requires as many as five different power poles! Two power poles of an alternating voltage of 4.25 Volts, power poles of +13.9 and -13.9 and one more mysterious power supply of +38 Volts. Therefore, the next rather boring part of the story is dedicated to the power supply.

    The power supply is based on the integrated driver of DC / DC converters - MC34063. The circuit is shown in fig. 2. With the purpose, I think everything is clear - to convert a certain amount of energy into the sum of some other energies needed to power the circuit. This amount was determined empirically, consumption currents were measured through power channels. From an alternating voltage source of 4.25 Volts, necessary for the filament of the indicator lamp, the current was 100 mA . From the +12 Volt pole, the current consumption was 12 mA , and from -12 Volt 10 mA . Current consumption on the +38 Volt channel is absolutely “penny” - 3 mA. Putting it all in the form of power, it turned out 0.803 watts. Considering that the main consumer is the filament, which is powered by a 4.25 Volt AC voltage source, these two values ​​- 4.25V / 1W - formed the basis for calculating the power supply. All other stresses were supposed to be obtained in a roundabout way. During the first test runs of the collider ... oh! - indicator, one nuance was identified associated with the power of the filament of the indicator lamp. It turned out that she "digests" a very bad voltage. This is due to the deep physics of the processes occurring inside the lamp, and I think it’s not worth digging into them. This is expressed in the uneven brightness of the glow of the anodes of the indicator. From the side of connecting the positive potential, they shine brighter. But from the opposite potential, zero, they do not shine, you can say at all. After this “discovery”, the circuit was supplemented with a key transistor DC / AC inverter. As a result, I got a circuit (see Fig. 2), which makes it possible to power our device from one power pole. I chose 12 volts. Power is supplied to the device through the standard Molex PC-8981 computer power connector.

    The most important part of the power supply is the choke. In our design, it is also an autotransformer, and just a transformer ... - solid “chemistry”. For my version, I chose the core B22 2000NM, or rather I didn’t choose it, but I just had one. A non-magnetic gap must be made in the core. This is done in order to avoid core saturation; it is also good for accumulating magnetic induction energy in the core.

    The easiest way to make a gap is to glue one cup of the core to a thin piece of paper. After the glue dries, the excess must be carefully trimmed with a scalpel. All windings are wound on a spool, which is then inserted into the core cups. Slots are provided for the leads of the windings in the cups. The main winding of this "inductor-transformer", primary, is indicated by I in the diagram. This winding is the only one that honestly calculated according to the formulas from the datasheet, all other windings were found from proportional ratios. The winding I contains 24 turns of wire with a diameter of 0.3 mm , the initial inductance is 250 uH (microgenry). Winding II and IV , 47 and 73 turns, respectively, wire diameter 0.2 mm . Winding III -143 turns, wires with a diameter of 0.1 mm .

    In order to further exacerbate the effect of mystery and to show the internal technological details of the indicator lamp, I used the backlight. The backlight is blue, and it’s not special, I just had two empty lighters with a “flashlight” at my disposal. And they lost their "flashlights." I note that the white backlight looks no less impressive, but I felt sorry for the white LED.


    Considering the fact that the device clearly marks the "incorruptible" discharge, I stock all the possible functionality for the future. In addition to two scale bars, six more mnemonic symbols can be displayed on the indicator. Their management is reserved as inputs for the logical levels of TTL. To match the logical levels of TTL and the levels of anode voltage of the segments, the K561PU8 microcircuit was used (Fig. 3).

    At the moment, the indicator is connected to the output of the computer’s sound card through the buffer amplifier and simply “twitches” in the music. Although he did not lose the functions of the measuring device with which he was before the barbarous alteration. And if anyone needs to know the signal level in dBu, then it is quite suitable for this task.
    In the future, there is a desire to puzzle this “blinker” more intelligently. For example, to force to show the speed of distribution / download to the torrent. A very attractive project on this topic can be found here .

    ATTENTION! The device has a pronounced hypnotic effect. Not recommended for long-term demonstrations to easily suggestible people. Demonstration to people who have not seen anything other than an LCD display with a touchscreen should be carried out with an introductory briefing: that it is not dangerous, that it is not from outer space and that it has nothing to do with the "green men".

    And finally, a video of the device.


    And one more thing

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