Piezo acoustic guitar pickup

Discussion in 'The Projects Forum' started by blah2222, May 6, 2011.

  1. blah2222

    Thread Starter Well-Known Member

    May 3, 2010
    554
    33
    Hi all,

    Just starting out with my little amplifier project and I just have a couple quick questions regarding the piezo pickup portion.

    I bought a Radioshack piezo buzzer, opened it up and got the piezo element out and I also have my 1/4" mono audio jack but I am unsure of what to connect.

    Firstly, for the piezo, it has three different contact points:

    [​IMG]

    What is the purpose of the center region connected to the blue wire? I am guessing that the brass is the grounding connection and the larger crystal portion is the signal. No idea what the small portion is for though.

    Also, once I figure out the connections for ground and signal for the piezo, where would I be connecting them to the 1/4" mono audio jack? This is the jack that I have:

    [​IMG]

    Thanks a lot!
     
  2. Audioguru

    New Member

    Dec 20, 2007
    9,411
    896
    The black and red wires will produce mostly the resonant frequency of the piezo (about 3kHz) like the sound it makes when it beeps. It will make a terrible microphone. If you can fasten it to the bridge of the guitar then it might pickup some lower frequency vibrations.

    You will not use the blue wire since it is the feedback connection for the transistor oscillator in the beeper.
     
    blah2222 likes this.
  3. blah2222

    Thread Starter Well-Known Member

    May 3, 2010
    554
    33
    Thanks for the reply! Well this is a tried and true method of making a cheap and effective guitar pickup, tons of great sounding pickups on youtube.

    Any idea for the audio jack connection?
     
  4. Audioguru

    New Member

    Dec 20, 2007
    9,411
    896
    Connect the audio jack the same as any other audio jack. The black wire goes to the sleeve for ground and the red wire goes to the tip as the signal.

    Maybe if you overload the piezo then it might have a wider bandwidth.
    One article says to place medium density foam against the piezo to dampen its resonance so it has a wider bandwidth. Another article says to glue only half the piezo to the bridge of the guitar then let the other half hang in the air to give a boost at around 3kHz.

    I think you got the wrong piezo since yours came from a cheap beeper (buzzer) but what is needed is a wide-range piezo transducer (speaker). The articles say to use a good one not a cheap one.
     
    blah2222 likes this.
  5. blah2222

    Thread Starter Well-Known Member

    May 3, 2010
    554
    33
    Sweet, thanks. FYI I have never done this before so I am glad someone could help. I'm not too picky with the piezo. I'm just following the guidelines and parts list of the tutorial. Hundreds of people seemed to get a good sound with little buzz, so for a first pickup, I think it'll be fine.
     
  6. #12

    Expert

    Nov 30, 2010
    16,306
    6,815
    I tried to make a piezo guitar pickup and amplifier many years ago, and I failed completely. It sounded like I left the battery out! Of course, I didn't have the internet at that time http://forum.allaboutcircuits.com/images/icons/icon7.gif

    If it simply doesn't work, you are not the first to do that. Just check in here and a few dozen people will tell you whatever they know.

    Hmmm...I guess I don't know how to do smileys, either.
     
  7. retched

    AAC Fanatic!

    Dec 5, 2009
    5,201
    312
    For a smiley, draw it. : ) without the space, ; ) without the space

    They show as; :) and ;)

    There are many more.

    If you click "GoAdvanced", you will get a "smiley" window. Just click the smiley you want to use, and it will place it in line at cursor location
     
  8. blah2222

    Thread Starter Well-Known Member

    May 3, 2010
    554
    33
    I don't know what you guys are talking about. I have wired this circuit up and have been using it with my acoustic and it sounds great... Unless you guys are noise nazis. Sounds good for a DIY amp.
     
  9. #12

    Expert

    Nov 30, 2010
    16,306
    6,815
    So...show me!
    I'd love to see how somebody else did what I failed at.
    :)
     
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