real time acquisiton and processing of EEG signal based on arduino board

[Kilwa]

Hi Haristhota,
this is my amplifier circuit and i wonder if i have had make a right connection to arduino.... 
i put one wire to A0 pin 
one to GND and the other to +5v

[Kilwa]

Hi Haristhota,
please can you check this figure and tell me am i acquiring an EEG signal ??
thanks for advance.

[Haristhota]

The ECG and EEG that you have posted are not actual signals. The actual signals may be referred from the chipstein blog that you have given the link earlier. ECG follows QRS pattern as shown in the blog and EEG you can verify by Eye blink artifact and FFT. 

I cannot comment on the circuit that you have posted since I don't know the description of that but I can suggest you following, 

1. Test the circuit at low gain for ECG acquisition by using an oscilloscope, you can follow the below configuration for ECG electrode placement. One electrode at the right arm, another one at left arm and DRL at right leg.

2. Verify your signal with standard ECG signal, don't worry even if you are getting noisy signal with right pattern (QRS)

3. Increase the gain (for EEG more gain is required) and try acquiring single channel EEG, place the electrodes at Fp1 & Fp2 positions and DRL at the mastiod position. Check whether you are getting eye blink artifact in your signal.

These are the preliminary checks you need to do for validation of your circuit.

Once you get proper analog signals from your circuit then its very easy to convert them into digital format by Arduino and you can acquire it to LV for further processing.

Try to acquire the signal at same baud rate ( should be same in Arduino code & LabVIEW setting) and bytes to read you can increase it to a higher value ( maybe 1000).

[Kilwa]

Hi Hir,
i have tasted my circuit and it gave me good result on oscilloscope ... i don't understand why it doesn't work with arduino and Labview ... i put the electrodes two in front of my head and the other on mastoid ... for the out put to  arduino i put one to A0 pin and the other on 3.3v and give me the result shown on the figure. i put both program on 9600 baud rates. 
i Have doubt on every thing now.. on batteries , on electrodes ... !!
Tell what to do :'( i don't have so much time.... 
PS: this is a link refer to my circuit http://eprints.utem.edu.my/16297/1/Neurofeedback%20Headband%20Controller%20Based%20On%20EEG%20Signal...

[Kilwa]

Hi Haristhota,
How can i increase the amplifier gain ? is it by adjusting the potentiometer i have 1M trimpot in my circuit... 

[Haristhota]

This is the article I referred long back to design a portable amplifier for my research. Go through this it answers everything  

[Kilwa]

okay, i really hope so.  
thanks a lot Haristhota. 

[Kilwa]

Hi Haristhota,
Can you, Please, help me and take a look on the picture and explin for me why do i get a signal like that ? 
thanks for advance.

[Haristhota]

I was out of the station I couldn't access the internet.

Looks like you are able to get some biopotential signals but they are very noisy.

Try to acquire atleast 10 seconds of data and plot the FFT, if are able to see a major peak at 50Hz/60Hz (USA) then apply notch filter and eliminate the powerline noise then you will get a clean biopotential signal.

If you are acquiring EEG, apply 4th order low-pass filter at 45Hz cutoff to find out the signal.

Hope this helps.

[Kilwa]

Hi   ,
Thanks for respond, this is really help. Well, i'am trying to acquire EEG and this is my first time using Labview.
Can you please be more generous and tell how can i apply 4th order low-pass filter at 45Hz cutoff to find out the signal???