Need help with constructing a piezoelectric circuit

Discussion in 'The Projects Forum' started by chiragdubey94, Dec 22, 2015.

  1. chiragdubey94

    Thread Starter New Member

    Dec 22, 2015
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    Hello.

    I am currently working on a project which requires me to design an electrical circuit.

    My aim is to use piezoelectric actuators in parallel (5-10 mm dia), and giving them a voltage of 9V using a signal generator. I want the actuators to vibrate in the 500-800 Hz range.

    Keeping in mind that I have to incorporate this in a light weight application, how do I proceed about this?

    Thank you.
     
  2. DickCappels

    Moderator

    Aug 21, 2008
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    It appears that you have already spelled out what you want to do, except the part about it being a light weight application is not clear. It seems you need to connect the transducer to the signal generator and set up the generator to output 9V (RMS?, P-P?) at the desired frequency.

    Is there more to your question?
     
  3. chiragdubey94

    Thread Starter New Member

    Dec 22, 2015
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    No, that's about it.

    All I want to understand is how to make the circuit, physically (wires and stuff). Being a student of mechanical engineering, I am drawing a blank at that.

    The signal generator will be kept outside the 'box', while the circuitry lies inside (transducers and wires).
     
  4. Dodgydave

    Distinguished Member

    Jun 22, 2012
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    So do you need an oscillator of 500-800 hz with a 9V square wave or sinewave output?

    For square wave use a 555 timer,
    For sinewave use a Wien oscillator.
     
  5. DickCappels

    Moderator

    Aug 21, 2008
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    Does your signal generator provide a high enough amplitude signal?

    If you can provide information on the transducers we can take a stab at it.
     
  6. #12

    Expert

    Nov 30, 2010
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    If each transducer has 2 wires, this is how you connect them.
     
  7. chiragdubey94

    Thread Starter New Member

    Dec 22, 2015
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    Wow, so many new things to learn here!

    Well, the signal generator isn't a problem. That can be arranged.

    The problem lies in circuitry itself. I am unaware of the specs of the transducers. I just know the diameter of them, which is around 5-10 mm. Anything above 9V will damage the transducers.

    See, if I have to place the transducers in parallel, preferably an array of 6. You can see a rough sketch. That is the top view. The small circles represent the actuators.

    The generator will be placed outside the 'box'. I just need help with figuring out a way to connect it.

    Keep in mind that the thickness of the 'box' is not more than 20 mm.
     
  8. DickCappels

    Moderator

    Aug 21, 2008
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    I think if you can follow the diagram in #12's post (post #6) you will get what you seek.

    An aside, if your signal generator has a DC offset switch, make sure it is off otherwise the transducers may eventually become damaged.
     
  9. hp1729

    Well-Known Member

    Nov 23, 2015
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    5 mm to 10 mm in diameter sounds pretty small. Can you provide a data sheet for the parts you are considering?
    Something like this?
     
    Last edited: Dec 24, 2015
  10. hp1729

    Well-Known Member

    Nov 23, 2015
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    Battery powered? How long do you want the batteries to last? Continuous service or intermittent?
     
  11. chiragdubey94

    Thread Starter New Member

    Dec 22, 2015
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    No, they aren't battery powered. The application is only producing vibrations in the frequency range of 500-800 Hz, for 9V p-p.

    And unfortunately, there are no battery sheets either.
     
  12. hp1729

    Well-Known Member

    Nov 23, 2015
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    No batteries???? What powers the oscillator? How much current do the transducers require? We can not do much without specifics of the transducers.

    So far we must have a battery that powers an oscillator running at 500 to 800 Hz driving undefined transducers. Are we okay so far?
     
  13. Hypatia's Protege

    Distinguished Member

    Mar 1, 2015
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    @chiragdubey94

    Inasmuch as (owing to their rather high unloaded Q) piezoelectric devices tend to exhibit wide and abrupt impedance variation with frequency -- I strongly advise implementation of a 'brute force' driver topology (e.g. an 'H-Bridge' arrangement, etc...)

    Best regards and good luck!:)
    HP
     
    recklessrog likes this.
  14. chiragdubey94

    Thread Starter New Member

    Dec 22, 2015
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    Update -

    So I gathered these piezoelectric discs and took them for a test run.

    On a breadboard, I placed four of them in parallel and gave them a frequency in the range of 200 Hz to 30 kHz, for maximum amplitude of the signal generator.

    All they did is made a buzzing noise at some frequency, but I couldn't notice any vibration whatsoever. They didn't vibrate like I expected them to.
     
  15. Dodgydave

    Distinguished Member

    Jun 22, 2012
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    What is the voltage amplitude of the signal from the signal generator,, does it work on just one piezo?
     
  16. chiragdubey94

    Thread Starter New Member

    Dec 22, 2015
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    well, peak to peak voltage was around maximum value, which is 20 if I am not mistaken.
     
  17. Hypatia's Protege

    Distinguished Member

    Mar 1, 2015
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    That's about what I'd expect -- What were you expecting?:confused: Tactile perception of vibration occurs only at rather low frequencies (< ~ 100Hz)...
    Again:
    In any case, good design will implement an active driver! --- Signal generators (in the sense used on this thread) are neither designed nor capable of supplying significant power...

    Once again, good luck!:)

    Best regards
    HP:)
     
  18. chiragdubey94

    Thread Starter New Member

    Dec 22, 2015
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    Okay, let us approach this from another perspective.

    Attached here is a figure, a rough sketch. This is how, ideally, I will be placing the actuator/piezoelectric disc. I want it to vibrate at the frequencies 500-800 Hz, no voltage specification at the moment.

    Attached here is also the picture of the disc which I used to run the first trial test, which was unsuccessful. I am not sure if I soldered it correctly.

    Please, let me know if you can help me.

    Thanks a ton. I really need all the help on this.
     
  19. Hypatia's Protege

    Distinguished Member

    Mar 1, 2015
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    Respectfully, with what do you require assistance beyond that already offered?

    Sincerely, best regards
    HP:)
     
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