accelerometer amplifier

Discussion in 'The Projects Forum' started by user_name, Aug 10, 2009.

  1. user_name

    Thread Starter New Member

    Aug 10, 2009
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    Hey guys Im trying to build an amplifier for an accelerometer. using a LM 741 op amp. I also get a lot of noise on the oscilloscope. I'm trying to really amplify the voltage. any suggestions on what set up I can use to? Thanks.
     
  2. hgmjr

    Moderator

    Jan 28, 2005
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    What is the part number of the accelerometer to which you are interfacing?

    hgmjr
     
  3. user_name

    Thread Starter New Member

    Aug 10, 2009
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    256HX Endevco
     
  4. hgmjr

    Moderator

    Jan 28, 2005
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    I notice from the datasheet that the sensitivity of the sensor is 10 mV/g. That seems very insensitivity. What is the level of acceleration in g's you are needing to measure?

    hgmjr
     
  5. user_name

    Thread Starter New Member

    Aug 10, 2009
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    I'm trying to get a measurement of about 2 g's
     
  6. hgmjr

    Moderator

    Jan 28, 2005
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    Would you be interested in a more sensitive measurement in the range of +/- 2g?

    Also, are you intending to use a microcontroller as part of your project?

    hgmjr
     
  7. user_name

    Thread Starter New Member

    Aug 10, 2009
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    For the sensitivity yes im interested in 2g's but i wont be using a micro controller.
    Ive been trying to recreate the circuit in this website (http://www.me.utexas.edu/~dsclab/labs/accelerometers/ex2.html) varying the resistors according to my gain calculation, but Ive had little success. Any ideas, thanks.
     
  8. ELECTRONERD

    Senior Member

    May 26, 2009
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    I wouldn't use the 741 op amp, it is far too noisy. I would suggest a low-noise instrumentation amplifier. You can find these from Texas Instruments, Analog Devices, and Intersil.
     
  9. jj_alukkas

    Well-Known Member

    Jan 8, 2009
    751
    5
    Try TL071/NE531/LF351/TL081 all are low noise, hi performance op-amps. Get a low noise op amp for your application. 741 is a general purpose, compensated op amp.
     
  10. ELECTRONERD

    Senior Member

    May 26, 2009
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    While these will work, an Instrumentation amp will be better. They are generally considered to be "unique op amps" since they provide the same functions of an op amp but provide better performance.
     
  11. hgmjr

    Moderator

    Jan 28, 2005
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    Once you have boosted the output of the accelerometer adequately, what is your plan for the output of the signal? How do you intend to use the output?

    hgmjr
     
  12. user_name

    Thread Starter New Member

    Aug 10, 2009
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    If I get this to work.. Im supposed to be measuring small oscillations. kinda like just put the accelerometer on the end of a ruler and pluck the ruler. a small cantilever beam, i want to get the sinusoidal wave for a long beam.
     
  13. ELECTRONERD

    Senior Member

    May 26, 2009
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    If you are supposed to get oscillations, I would hook the output of the device to an oscilloscope. Then you can see if your getting a applicable waveform corresponding to the correct waveform.
     
  14. user_name

    Thread Starter New Member

    Aug 10, 2009
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    yes i have an oscilloscope, i work in a lab.
     
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