Sensor signal amplification problem need help!!

Discussion in 'The Projects Forum' started by nenadilic84, Feb 13, 2010.

  1. nenadilic84

    Thread Starter Active Member

    Aug 7, 2009
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    0
    Hi,
    I have a piezoelectric sensor that measures pressure. When the pressing force is applied to the surface of the sensor the sensor outputs positive voltage to about 1.2 Volts max. When puling force is applied the sensor outputs negative voltage 1.2 volts max. In order to display this to the end user and process the data I need to make a small linear amplifier that amplifies the signal to dc ofsset 5 Volts, meaning that -1.2 will display 0 Volts and 1.2 will display 5 Volts. I have seen some circuits using an op amp, but I don't now where to start what op amp should i use, and etc.

    Thanks,
    Nenad
     
  2. nenadilic84

    Thread Starter Active Member

    Aug 7, 2009
    62
    0
    Something like this... But what op amp to use and ect...
     
  3. MikeML

    AAC Fanatic!

    Oct 2, 2009
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    Something like that. Since this is happening at hand motion speeds, then you do not need a high speed opamp, right?

    Need one more piece of info. What impedance can the sensor drive? That should be on the data sheet. The posted circuit does not have a high input impedance, which the sensor might need...
     
  4. BMorse

    Senior Member

    Sep 26, 2009
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    234
    Try something like this, it will take any voltage level from the Piezo (negative or positive) and convert it to a + voltage output... the 100K potentiometer will give you some adjustment to the output of the piezo...

    Piezo Buffer.png
     
  5. MikeML

    AAC Fanatic!

    Oct 2, 2009
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    Mr Morse, I think the OP needs a DC-coupled amplifier.
     
  6. nenadilic84

    Thread Starter Active Member

    Aug 7, 2009
    62
    0
    Thank you... I think this will do the job..

    Thanks again,
    Nenad
     
  7. BMorse

    Senior Member

    Sep 26, 2009
    2,675
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    This circuit will take positive or negative voltage level from the piezo but it always outputs a positive voltage... I use this in my 16 Channel (Piezo triggered) MIDI drum trigger module [​IMG].........:rolleyes:

    http://www.morse-code.com/id208.htm
     
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