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DDS generator, my version of the Chinese module housing.

dudik56 9477 34
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  • DDS generator, my version of the Chinese module housing.
    I have been using the Chinese DDS generator module for some time, I got tired of the makeshift of this device, the lack of a housing, a spider power supply from some li-ion batteries and converters, so I decided to sort it out inspired by previous publications on the electrode.

    Having some time and electro-scrap metal, I made the housing using metal sheets and a front from a CD-ROM drive. I cut out the dibond front panel and glued it to the converted front of the drive.
    Originally, for menu navigation, I wanted to use ready-made keys from recycled material, but they turned out to be flimsy and I made the ring, keys and knobs by turning from aluminum. The + 12V, -12V, + 5V power supply was made on a universal laminate using LM 78XX and LM7912 stabilizers and a 2x12V transformer. Having little space on the front panel where only a small key can fit, I placed the power switch on the back next to the transformer. On the smoky display pane, I stuck the inscriptions on the foil concerning sockets and knobs, with the backlight they are sufficiently visible. I did not describe the navigation keys because you intuitively know where the top, bottom, left and right are, in the middle OK and this tiny one is a reset.
    I do not include the diagram because I don't have it. I often use enclosures from drives to pack my various devices. The photos show the effect of my work ;)
    DDS generator, my version of the Chinese module housing.

    DDS generator, my version of the Chinese module housing.

    DDS generator, my version of the Chinese module housing.
    and that's how it found a place on my shelf ;)

    DDS generator, my version of the Chinese module housing.

    Cool? Ranking DIY
    About Author
    dudik56
    Level 17  
    Offline 
    dudik56 wrote 322 posts with rating 602, helped 4 times. Live in city Świebodzice. Been with us since 2010 year.
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  • #2 19258270
    ArturAVS
    Moderator
    Interesting design, although I would have reservations about these protruding display frames. It breaks down all the aesthetics.
  • #3 19258290
    dudik56
    Level 17  
    ArturAVS wrote:
    Interesting design, although I would have reservations about these protruding display frames. It breaks down all the aesthetics.

    These protruding frames are in my earlier devices, I was already rolled over for these frames ;) that's why I didn't make this mistake this time and the display is too fast.
  • #4 19258313
    ArturAVS
    Moderator
    I have to clean up my DDS, and the idea of an optical drive box is a great idea. Plus for that.
  • #5 19258519
    anszun
    Level 18  
    I like it very much. I like it this way. The device is not a Christmas tree to watch, but something that is often exposed to accidental damage while working. this case certainly meets this condition. By the way, write how the generator works, is it stable, how it works with a frequency meter, etc., how do you evaluate the device itself.
  • #6 19258591
    dudik56
    Level 17  
    anszun wrote:
    By the way, write how the generator works, is it stable, how it works with a frequency meter, etc., how do you evaluate the device itself.


    As for such a cheap, I am amazed by its indications, they coincide to 1Hz. I temporarily connected the oscilloscope and both devices show the same ;)

    DDS generator, my version of the Chinese module housing.

    DDS generator, my version of the Chinese module housing.
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  • #7 19258725
    anszun
    Level 18  
    that's great :) And can you tell me what the generation range is?
  • #9 19259011
    anszun
    Level 18  
    Thanks for the links :) I have already tracked the Chinese and I will make a housing similar to yours.
  • #10 19259052
    zgierzman
    Level 31  
    anszun wrote:
    Thanks for the links :) I have already tracked the Chinese and I will make a housing similar to yours.


    But maybe security is more concerned than the author of the thread. 230 VAC fits onto a universal unit hanging millimeters above the metal casing. Well, some piece of paper underneath ... And the protective conductor cannot be seen even at high magnification.

    DDS generator, my version of the Chinese module housing.
  • #11 19259105
    dudik56
    Level 17  
    zgierzman wrote:


    But maybe security is more concerned than the author of the thread. 230 VAC fits onto a universal unit hanging millimeters above the metal casing. Well, some piece of paper underneath ... And the protective conductor cannot be seen even at high magnification.

    Thanks for your vigilance ;)
    I've thought about it too, but it's not too bad ;) There is quite a thick plastic plate on the spacers under the entire plate of the power supply, not a piece of paper, and nothing bad will happen here, as for the protective conductor, it is actually not there, but the whole set in the post is twisted in a common metal frame removed from the computer housing and it is connected to the protective conductor from other devices.
  • #12 19259133
    pawlik118
    Level 33  
    Well, but from the place where the blue wire is soldered to the board, and the mounting screw to the housing is maybe ... with 0.5mm? And it should be 10mm. The switch is also probably not adapted to 230V.
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  • #13 19259195
    dudik56
    Level 17  
    pawlik118 wrote:
    well, but from the place of soldering the blue wire to the board and the mounting screw to the housing, maybe .. with 0.5mm? and it should be 10mm. The switch is also probably not adapted to 230V.


    The switch is really delicate, but with a 2.5W transformer, its load current is around 10mA and it works fine, I had trouble finding a sufficiently small fuse ;)
    The distance of the cable is 6mm and it is maybe too small, but for the sake of peace, I will put on higher distances made of polyethylene, I still have a lot of them.

    DDS generator, my version of the Chinese module housing.
  • #14 19259253
    pawlik118
    Level 33  
    As for the switch, I meant the operating voltage - in terms of insulation to the metal button rod.
  • #15 19259271
    dudik56
    Level 17  
    I understand, I can roll a plastic rod connector and switch, it's 5 minutes of work ;) I'll think about it again. Thanks for your comments.

    I corrected, the distances higher and insulated, I replaced the switch connector with a plastic one.
    about..
    DDS generator, my version of the Chinese module housing.
  • #16 19259677
    kapi11711
    Level 14  
    Personally, this type of housing does not appeal to me (I have been against upcycling for some time), but overall it looks really neat and I believe that the author likes it, a plus.

    The second - a very big plus, for the actual implementation of my colleague's advice on the distance of wires with mains voltage the housing - very respectable, because in most threads in DIY Konstrukcje, the author of the topic says that he will apply corrections, change, improve, and then no response, I hope that the lack of a correction in those projects does not cause any injuries, which make the authors unable to write back ;)
  • #17 19259830
    ^ToM^
    Level 42  
    Nice. Plus from me for making a power switch with a long pusher. A solution known from factory equipment (Philips or Hameg).
    This allows you to move away with the power supply and power switch and 230 V power cables to the back of the device, which often has an impact on the output parameters of the device.

    Regards!
  • #18 19259890
    ArturAVS
    Moderator
    ^ToM^ wrote:
    A solution known from factory equipment (Philips or Hameg)

    Not only. For me, this generator lacks a smooth frequency change, which in the case of "digital" waveforms does not bother me, but in the audio range (eg 20Hz-20kHz) it would be useful.
  • #19 19260130
    czareqpl
    Level 33  
    dudik56 wrote:
    I understand, I can roll a plastic rod connector and switch, it's 5 minutes of work ;) I'll think about it again. Thanks for your comments.

    I corrected, the distances higher and insulated, I replaced the switch connector with a plastic one.
    about..
    DDS generator, my version of the Chinese module housing.


    I am not sure whether it is in the case of a metal housing, where theoretically there may be potential on the elements susceptible to touch obligatory is to route the protective conductor and ensure its potential on all exposed parts of the equipment?

    I am asking my colleagues sitting in the electro-safety industry to comment.

    To the author: Please do not take it as a strong criticism, but someone else, less experienced and less tidy, may follow your project. It may not tighten the cable properly, or the tip may detach from the solder point.
  • #20 19260138
    damian1115
    Level 37  
    Very nice neat workmanship, fits nicely with the rest of the equipment. A plus for aesthetics.
  • #21 19260188
    dudik56
    Level 17  
    czareqpl wrote:

    To the author: Please do not take it as a strong criticism, but someone else, less experienced and less tidy, may follow your project. It may not tighten the cable properly, or the tip may detach from the solder point.


    Thanks for your comments, I have already explained the grounding issue how it works in my case. For the expected adventures with the cable, I made a really solid cable holder from polycarbonate, because the ready-made ones did not inspire my confidence. So breaking the tip off the solder point is out of the question. Besides, the generator once installed will live there and no maneuvering with the cable will be necessary.
  • #22 19260225
    żarówka rtęciowa
    Level 37  
    Hello

    In such a construction, a transformer mounted to the housing (with a clamp) can be used.

    pawlik118 wrote:
    Well, but from the place where the blue wire is soldered to the board, and the mounting screw to the housing is maybe ... with 0.5mm? And it should be 10mm. The switch is also probably not adapted to 230V.


    It can be placed on the secondary side of the power supply, a method quite commonly used in low power mains powered devices. In this design, it would have to be with at least two pairs of contacts.
  • #23 19260986
    U92
    Level 10  
    czareqpl wrote:
    I am not sure whether it is in the case of a metal housing, where theoretically there may be potential on the elements susceptible to touch obligatory is to route the protective conductor and ensure its potential on all exposed parts of the equipment?

    I am asking my colleagues sitting in the electro-safety industry to comment

    No, it is not obligatory and it has been done by the holder who is aware of the risk of using it.
  • #24 19261095
    dudik56
    Level 17  
    U92 wrote:

    No, it is not obligatory and it has been done by the holder who is aware of the risk of using it.


    A lot of modern factory equipment, such as tuners, amplifiers, cd players, etc., is powered by a two-wire cable and have metal fronts and housings.

    Going back to the generator, I replaced the LM358 with TL062 in it and I obtained a smooth course of the function when passing through zero, without an offset. This is a known modification of this DDS.
  • #25 19261128
    zgierzman
    Level 31  
    dudik56 wrote:
    I replaced the LM358 with TL062 in it and got a smooth zero-crossing function, without an offset.


    It's not an offset rather, but a cross-distortion ...
    An offset is when the entire waveform is offset up / down from zero. Most generators, even the cheapest Chinese inventions, have the ability to adjust the offset, even with a potentiometer.
  • #26 19261143
    dudik56
    Level 17  
    zgierzman wrote:

    An offset is when the entire waveform is offset up / down from zero.


    Well .. I just have a knob what it does ;)
  • #27 19261216
    .Wiśnia
    Level 28  
    you clamp the phase and neutral wires through aluminum? you do not provide any protection class, the device has the potential to cause an electric shock. For your own sake and for the sake of others, change the power cord to a 3-core PE wire and screw the housing to this wire.
  • #28 19261225
    dudik56
    Level 17  
    .Wiśnia wrote:
    you clamp the phase and neutral wires through aluminum? .

    I guess you just looked at the photos, did not read how and what the clamped wires are and how the grounding of the whole is implemented. But thanks for your concern.
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  • #29 19261258
    anszun
    Level 18  
    Earlier, the author wrote that he changed the clamp to made of plastic. Besides, it seems to me that there is no place (apart from the connections to the primary of the transformer - and this seems to be protected) that can short-circuit to ground. The transformer itself (flooded, by the way), in this case already fulfills the protection on the secondary side. After all, it is not a high-powered energy device :) The factory equipment of Diora, varieties of eltrons, etc., were sown with two wires. Of course, if someone is stubborn, he can build an overcurrent switch on the box, so he he looks nice too.
  • #30 19261283
    .Wiśnia
    Level 28  
    Dear colleague, this is not a module but a separate device, so you connected. Taking a protective wire from another device, no comment.
    Ask yourself if someone else can touch it and if so, swap the wire as soon as possible.

    It always seemed to me that work in the workshop is particularly exposed to ..... you can insist on your own, but no electrician would sign it.

Topic summary

The discussion revolves around a DIY project involving a Chinese DDS (Direct Digital Synthesis) generator module. The creator expresses dissatisfaction with the original module's makeshift design and lack of housing, prompting them to construct a custom metal enclosure using scrap materials, including a front panel from a CD-ROM drive. The power supply is designed with LM 78XX and LM7912 voltage regulators, and the user addresses concerns about safety, grounding, and insulation. Feedback from other users includes suggestions for improvements, inquiries about the generator's performance, and discussions on electrical safety standards. The generator reportedly provides stable frequency output, with modifications made to enhance its functionality.
Summary generated by the language model.
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