EMG signal analysis

[kapillohia]

thank you very much sir.. it means i can amplify the signal with the DAQ assistant itself. can u tell me how much gain i can draw using that PCI 6221 daq. the emg signal fall up to 15mV and  upto 300 hz. if u have a daq configuration ready for the EMG can u pls tell me.

[NI-Bongo · Accepted solution]

Hello kapillohia,

The gain is automatically added when you change the Signal Input Range, so you don't need to do anything to configure it or scale your data. 

If you want to see the gain being applied on a given channel, you can use the DAQmx Channel Property Node and read the property under Analog Input»General Properties»Advanced»Gain»Gain Value.  To put this property into your code:

1. Right-click on your DAQ Assistant icon and select Generate NI-DAQmx Code.
2. Place the DAQmx Channel Property node between the generated configuration subVI and the DAQmx Read VI.
3. Delete the task and error wires between the generated configuration subVI and the DAQmx Read VI.
4. Wire the task and error wires from the enerated configuration subVI to the property node.
5. Wire the task and error wires from the property node to the DAQmx Read VI.
6. Set the property to Analog Input»General Properties»Advanced»Gain»Gain Value. 
7. Create an indicator to see the gain value on the front panel.

[kapillohia]

thank you very much sir.. i will try and then mail you.

can you give me your email id

[NI-Bongo]

Hi Kapillohia,

To get in touch with us directly, please follow this link to generate a service request:

Request Support
http://sine.ni.com/apps/utf8/niae_asc.main

You can reference a link to this forum in your request as well to avoid having to reexplain things in your request.

[viginesh]

Hello Siju,

            I am very happy that you work to acquire  EEG.  My project is processing EEG for neurological disorder. Could you please mail me the acqired data. So that i could use it.

My Id is vignesh_31@yahoo.com

Thank you in advance

[siju]

Hi vignesh.,

I would like to help u , but the project was done 2  years back in college and now i am in work place .So , when i get back to my home town , i will send it 2 u

[viginesh]

Hi Siju,

    Thank You very much.Kindly try to help me with rememberance. I would be so thankful.

[Steve.J]

PLEASE do not attempt to acquire signals directly using a NI DAQ board or any NI signal conditioning products.  NI does not make any hardware that is suitable for direct connection to ANY living organism.  There are two big problems: 

1. SAFETY - you need an isolated amplifier system with appropriate safety certifications (UL 60601-1 or EN60601-1) which is critical to provide protection against shocks and/or burns in the case of an electrical fault.  And not just faults originating from the EEG system - also protection from providing a ground path for electrical faults originating from some other device that may come into contact with the subject.

2. PERFORMANCE - surface biosignals (EEG, EMG, ECG, etc.) require specialized amplifiers to acquire cleanly.  The signals are riding on top of 56/60Hz line frequency interference that is often orders of magnitude greater than the actual biosignal. The signals are also riding on a large DC offset generated by the electrodes and electrolyte used to make a good connection with the skin, and the source impedance (electrode to skin/body) is high (5-10Kohms or more) and often badly mismatched.  Signal conditioners for biosignals are designed specially to deal with these issues - they are usually AC coupled, have adjustable low and high pass filters (and often a notch filter at the line frequency) to block the offset potential and prevent noise from being digitized and aliased, have multiple stages of gain to reduce amplifier blocking (saturation) due to movement and other transients, and have very high impedance balanced inputs (high CMRR) to reject the common-mode noise and only amplify the signal of interest.  

Specialized amplifiers are available from a number of sources and have high-level analog outputs that are ready to be digitized by an NI DAQ board.  Look at companies like Grass Technologies, AD Instruments, MIndware Technologies, and others.

Steve

[siju]

Before that , u hav to design a signal conditioning unit which would modify the signal acquired so that it is read by the card.

hav u decided which card to use?

[amitpathak]

i am doing my project on eeg signal analysis.i am facing some problem in the the initial stage because i am not getting the raw eeg signal. if possible please send EEG signal in text format or other format .