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Adding audio jack to childrens learning toy

Discussion in 'General Electronics Chat' started by JamesTrix, Jan 5, 2017.

  1. JamesTrix

    JamesTrix New Member

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    Hello, its been a while since college and my electronic knowledge has all but dried up. I am working with some school children on an electronic learning device and wanted to get some help by improving it.

    At the moment it has a standard speaker but it's hard to hear in a classroom. I wanted to see if I could wire in an audio jack. I have attached the circuit board and have been able to salvage jack from another project. It's a TRRS SMD audio jack but I was looking for advice on how best to wire this in.

    Thanks for any advice or help you can give

    [​IMG]
     
  2. audioguru

    audioguru Well-Known Member Most Helpful Member

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    Your attachment does not work.
    It is easy to connect a jack to the speaker and even have the speaker switched off by the jack when you plug a cord into it. Your cord will probably connect to an amplifier input. I modified my cheap clock radio to produce hifi with deep bass sounds into an external speaker with a jack.
     
  3. JamesTrix

    JamesTrix New Member

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    Sorry that the image is not showing for you here is the direct link to the image

    https://s30.postimg.org/xjav1fh3l/IMAG0699.jpg

    Having the auto off function of the audio jack would be nice is a TRRS jack able to do that ? How should I wire in the jack ?
     
  4. dave

    Dave New Member

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  5. audioguru

    audioguru Well-Known Member Most Helpful Member

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    I do not think your jack has a switched speaker connection. A Tip Ring Ring Sleeve jack is Left channel, Right channel, commons and microphone. The speaker output from the toy needs an attenuator circuit so that it does not overload the microphone input on your audio system. Use a mono jack and feed it into a line input on your audio system instead. If you want stereo and to feed the microphone input I can design the attenuator for you to try.
     
  6. JamesTrix

    JamesTrix New Member

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    Thanks for the feedback, I have attached a picture of the audio jack that I was able to pull from another device it only has 3 pins in it, The idea would be to feed the audio to a set of headphones or PC speakers. The current jack would just fit in the current case if I did some Dremel work.

    If that jack won't work and you recommend a switched speaker connection then let me know and I will see if I can order one.


    https://s27.postimg.org/6k1l0mboz/IMAG0698.jpg

    [​IMG]
     
  7. audioguru

    audioguru Well-Known Member Most Helpful Member

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  8. JamesTrix

    JamesTrix New Member

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    Thanks for the help again audioguro, I had a look at the MJ-3523-SMT-TR / CP-3523MJTR-ND

    In terms of size it looks good and I could solder the ends to the surface mount tabs, as its mono am I right in saying the I won't need an attenuator ? The recording is all spoken word.
     
  9. audioguru

    audioguru Well-Known Member Most Helpful Member

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    Mono or stereo and speech or music have nothing to do with needing an attenuator. The level from the speaker of the toy might be 50 times too high if it is fed to a "microphone input" so of course an attenuator is needed to reduce the level.
    An attenuator is not needed of the signal is fed to a "line input" or "aux input".
     
  10. JamesTrix

    JamesTrix New Member

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    Thanks for trying to educate me on something that I don't have much clue on audioguru, the input will be fed to a set of earphones could I get around this by using a set of ear phones with a volume controller ?

    Or would you have the time to design the attenuator for me ?
     
  11. audioguru

    audioguru Well-Known Member Most Helpful Member

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    Now you talk about earphones instead of in your first post.
    Earphones are not connected to an input, instead they are connected to an output. You are connecting the jack to a speaker output so when you plug in, then the speaker will be disconnected by the switch on the jack and normal but a little too loud sounds will be fed to the earphones. I hope you do not have earphones with a 4-connections plug that is used for a cell phone. Instead you probably have stereo earphones that will play in only one ear when plugged into a mono jack.

    I thought that since the tiny speaker on the toy was hard to hear in the classroom then you were feeding the output signal from the toy to an amplifier microphone input on an audio system.
     
  12. JamesTrix

    JamesTrix New Member

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    Sorry audioguru I was thinking to feed the audio from the learning toy into a set of headphones so they could hear it better. I have not purchased a jack as yet until I know for sure it will all work as wella s how to wire in the jack correctly.
     
  13. audioguru

    audioguru Well-Known Member Most Helpful Member

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    If the headphones have a stereo plug (tip, ring and sleeve) without a microphone then buy a stereo switched jack.
     
  14. dr pepper

    dr pepper Well-Known Member

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    Hi James, welcome.
    Headphones shouldnt be too hard to connect up, however have you thought about a bigger speaker, the one thats fitted is probably very innefficient, if you salvaged a 6 or 8" speaker from some scrap equipment it would probably make a big improvement if you have the space for one.
     

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