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Electronics 5.1 - Headphone Switch

Discussion in 'Modding' started by Devil_H@ck, 25 May 2003.

  1. Devil_H@ck

    Devil_H@ck What's a Dremel?

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    I want to use this circuit to turn off the audio signal to my 5.1 boxes when I insert my headphone in the specified switch.
    Would this work? I'm not really good at electronics, so any help is welcome.

    The circuit below is a new version. See below for more details.

    [​IMG]
     
    Last edited: 26 May 2003
  2. SteveyG

    SteveyG Electromodder

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    It would work, but its a very very poor design and I'd personally steer well clear of it. You could make a better design that would have better results using a set of relays, so long as you have nothing against relays, because the current design would drastically reduce the quality of the sound. Maybe you could use some CMOS bilateral switches instead? Just be sure to use a split supply for these (+/- 7.5V).
     
  3. Devil_H@ck

    Devil_H@ck What's a Dremel?

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    Hm, so it would work? Cool, I haven't got electronics at school so I'm proud of myself ;).

    But what are those CMOS bilateral switches you are talking about? Could you explain it a bit more pls, because the clicking sound of relays makes me nervous :).
    And yes, I know that there are non-clicking relays, but they seem to be expensive, or would this CMOS thing be even more expensive?

    *mod: Hm, I think that those CMOS chips you're talking about arae actually the non-clicking relays I am talking about.
    I asked for one once in an electronics shop and the guy showed me a chip so ...
     
    Last edited: 26 May 2003
  4. Devil_H@ck

    Devil_H@ck What's a Dremel?

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    Ok, I posted a new version.

    I added 1 functionality because someone over at Shrimpwars forum asked.

    The DPDT switch is used to switch between auto-modus (this automaticly turns of the boxes when a headphone is inserted) and manual mode (you can chose what is activated by switching the SPST switch).

    Would this work? I know it's probably way to complicated, but well, it was the only thing I could come up with.

    The relays are in the 'no-headphone-inserted' modus, so they are on when they are not powered, because I assume most people will be using their boxes most of the time. This way the circuit will consume less power.

    I'm using the 2 NOR ports (which I'm using as NOT ports) because if I don't I think I will draw a lot of current from the headphone connection, causing terrible sound.

    *mod: Damn, I noticed the headphone relay is off when the circuit is in auto-mode.
    I'll try to come up with something tomorrow.

    All help is welcome :).

    **mod 2: Would it work if I connect the 2nd contact of the DPDT switch when in auto-mode to the NOR port? So that the headphone relay will always be on when in auto-mode.
     
    Last edited: 26 May 2003
  5. Devil_H@ck

    Devil_H@ck What's a Dremel?

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    Ok, once again I've edited the schematics.
    I'm using an inverter now, I suppose this is the same as a NOT port (the symbol's the same I think)?

    I've reagaranged the schematic a bit and I think everything should be correct now.

    I've also deleted the relays on the right and left audio channel and instead put on on the ground line. Would that work or is there a connection between the left and right audio channel?

    Here's the circuit, tell me if something is wrong pls.
    [​IMG]

    *mod: I edited the circuit, relays are on left and right audio channel again. I also changed the relay for the headphone from ground to left and right channel.
     
    Last edited: 27 May 2003
  6. SteveyG

    SteveyG Electromodder

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    Most headphone jacks will have an extra little terminal on them that work as a switch when the plug in inserted/removed, so you'd do better by using this extra terminal to turn your relays on.
    Secondly, its not a great idea to have the switches on the GND/shield since the chances are you'll still get some output from the speakers, though it will be very distorted.
    You need to have the relays switching the signal lines.

    I'll draw you up a quick circuit later tonight when I get back.
     
  7. Devil_H@ck

    Devil_H@ck What's a Dremel?

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    Hm, ok, I thought of that, I'll take a look at it later tonight.
    And I'll readd the relays to the channel wires.

    *mod: About that connection on audio jacks, I'd have to suply a +V signal to it in order to see if something was connected or not, right?

    I'll go change my circuit right now :).

    **mod 2: Hm, I can't think of any decent way of using that extra terminal on a headphone jack. I'd have to send +V through it and then block the +V when something is inserted and ....
    Unless someone knows an easy way, I'm sticking with my current method, I'll just use a very high value for the resistor, so that I don't notice any distortion on the sound.
     
    Last edited: 27 May 2003
  8. SteveyG

    SteveyG Electromodder

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    I've not had time to draw up a diagram, but you can just connect the relay to +12V or +5V, and the other lead from the coil to the terminal on the jack, so that when the plug is inserted, the relay is turned on. Just use the NO or NC terminals on this relay to control the others. No resistors needed, and the only diode you'll need is the one blocking cemf from the coil.

    I don't quite understand your diagrams because you seem to have no connections for the coil of the relays???
     
  9. Devil_H@ck

    Devil_H@ck What's a Dremel?

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    Hm, it seems I had uploaded a ****ed up version.
    It should be correct now.

    Still, I don't understand how exactly I'm going to use that extra connection on the plug.
    Won't the +12V or +5V interfere with the audio signal?
    Could you pls draw a scheme of that (the left part of my circuit, but the way you propose to do it)?
     
  10. Devil_H@ck

    Devil_H@ck What's a Dremel?

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    Ok, once again, a 'better' version (read: more wires all over the place). I changed the weird relays to normal ones, allowing me to test the circuit in simulation mode, everything seems to be working correctly.
    I've also added a diode after the switch, to prevent power going through the other diode, thus setting the NOR ports output to 1.
     
  11. Devil_H@ck

    Devil_H@ck What's a Dremel?

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    I was wondering, maybe it would be better for the 7404 if I connected the output to a transistor instead of to all of the relays.
    That would be better right?
     
  12. SteveyG

    SteveyG Electromodder

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    Something simple like this would work (obviously adding relays for the extra channels).
    If I remember correctly, the extra connector is connected to the shield when the jack is inserted.

    It won't introduce any noise with the relay connected as it is provided you have a proper common connection between all three jacks and the GND of your power supply.

    [​IMG]

    The circuit as you've drawn it won't operate because the TTL devices don't have enough current to sink more than a few mA, so yes, you'd need some transistors.
     
    Last edited: 30 May 2003
  13. Devil_H@ck

    Devil_H@ck What's a Dremel?

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    Ok, I tried, but I don't get your schematic :).
    Too much black, pen stuff ;).

    But, what you're saying is that my circuit would work perfectly if I used transistors, right?
    And I think my circuit is also one of the simpelest for the thing I'm trying to make right?
     
  14. SteveyG

    SteveyG Electromodder

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    I can't see why it wouldn't provided you used transistors, but it isn't the most simple configuration by far, and there's a relay with no coil, so I'm still not quite sure what this circuit is going to do...

    You also need diodes in inverse parallel on every relay coil.
     
    Last edited: 30 May 2003
  15. Devil_H@ck

    Devil_H@ck What's a Dremel?

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    Hm, check the image again, all relays are 'normal' now.
    Any idea what transistor I should use?
    I don't know how much current the relays need, I'm planning on using these: http://www.velleman.be/common/product.Aspx?id=17784
    How much current would they need?

    I'll upload a modified circuit later tonight, with the anti-parallel diodes. Why are they necessary anyway?
     
  16. Devil_H@ck

    Devil_H@ck What's a Dremel?

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    ** nothing here :worried: **
     
    Last edited: 13 Jun 2003
  17. SteveyG

    SteveyG Electromodder

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    You've got 8 relays there, so the total would probably be about 240mA. A 2N2222 would work, or BFY52.

    The diodes (1N4148) are there to reduce back emf from the relays.
     
  18. Devil_H@ck

    Devil_H@ck What's a Dremel?

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    Well, no actually I'll have 4 relays. (4x 2x inverted).
    But I can't get that in a decent way in the program.
    So that would be 120 mA right?
     
  19. SteveyG

    SteveyG Electromodder

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    I assumed you were using 12V relays. 5V ones have a typical resistance of around 100 ohms, so the total will be around 200mA. It depends on the individual relay you use as to the exact current draw.

    It'll work better if you move the relays to the other side of the transistor (so the relays are constantly connected to the +5V), otherwise you might not be able to pull the full current needed through the transistor.
     
  20. Devil_H@ck

    Devil_H@ck What's a Dremel?

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    Hm, thanks for that.
    I don't get it, the difference between collector and emitter-circuits :).
    And thx for the info about the relays, I didn't know why they put the resistance of it on the site (stupid :)).
    It's a 6v relay, but I suppose they'll work @ 5v too.
     

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