Troubleshooting EMG Circuit

Discussion in 'The Projects Forum' started by Antmoney999, Dec 5, 2015.

  1. Antmoney999

    Thread Starter New Member

    Oct 15, 2015
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    Hello all,

    For about a month or two now I have been researching various EMG circuits trying to learn what parts were essential for a basic circuit. After I thought I had a pretty good about what I needed to do I sat down and came up with this circuit. I assembled the circuit on a breadboard with a separate dual 5 volt supply on a different breadboard. When I connect it to the analog input of my arduino uno the values are just random, from what I can tell it's all noise. I cannot figure out whats wrong with the circuit, I've tried several things with no success. If anyone could help I would greatly appreciate it.

    Thanks,
    Anthony

    myEMGCircuit.jpg
     
  2. SLK001

    Well-Known Member

    Nov 29, 2011
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    What the heck is an EMG? Do you think that we can read your mind? Some of us can, but at this distance, it is pretty dicey.
     
  3. KMoffett

    AAC Fanatic!

    Dec 19, 2007
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  4. RichardO

    Well-Known Member

    May 4, 2013
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    Because this is a small signal, the wiring is critical to proper operation. The wires must be short and a star grounding system has to be used.

    A picture of how you have wired your circuits would help us help you better.
     
  5. Alec_t

    AAC Fanatic!

    Sep 17, 2013
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    That could be the main reason for the noise. Lengthy conductors and stray capacitance/inductance can pick up and couple noise into your circuit. As stated, wiring is critical.
     
  6. Antmoney999

    Thread Starter New Member

    Oct 15, 2015
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    I have attached the schematic in my original post. Here are pictures of the actual circuit, I have switched to the Arduino Nano just to make everything more compact.
    IMAG0759.jpg IMAG0760.jpg IMAG0761.jpg
     
  7. Alec_t

    AAC Fanatic!

    Sep 17, 2013
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    Are those three electrode leads screened?
     
  8. Antmoney999

    Thread Starter New Member

    Oct 15, 2015
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    I'm not too sure but I'm going to say they aren't.
     
  9. Sensacell

    Well-Known Member

    Jun 19, 2012
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    EMG signals are down at microvolt levels.

    You cannot expect to get this kind of low noise performance from a sketchy pile of solderless bread boards.
    With RF and microvolt signals, the layout and construction becomes critical to circuit function.

    This is where electronics becomes an art, no longer just a connect-the-parts exercise.
     
  10. Alec_t

    AAC Fanatic!

    Sep 17, 2013
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    This suggests that even if there are screen conductors you're not using them. A guaranteed source of noise input then :(.
     
  11. bonsaimaster1

    New Member

    Feb 8, 2013
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    SLK001, please try to control yourself. Your sarcasm and rudeness will not get you anywhere in life!
     
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