Re: OpenEEG Questions

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I am not, really... :D
Can you please define "leads"? Do you mean channels?
And what challenges?

OpenEEG is in default built as bipolar EEG. That means for each channel you
need to connect two electrodes. The output is difference of voltage between
those two electrodes. But even with two electrodes you won't need to make
two amplfication circuits. The difference of voltages is processed in the
instrumentation amplifier (first amplifier) and then the one difference
signal is amplified further, so it can be reliably converted to digital
data. So you will need an amplification circuit (cascade) for each channel
(2 electrodes).
OpenEEG with v2 protocol and baud rate 115200 can support up to 6 channels,
although ATmega16 can support 8. If there is need for more channels, you
would have to rewrite the firmware and change the baud rate. But with that
you would lose compatibility with software supporting OpenEEG (like
BrainBay).
I simply chose not to face those challenges and I stuck to the
specifications concerning OpenEEG compatibility. I use olimex v2 protocol
firmware with ATmega16L.



On Sun, Sep 20, 2020, 23:18 Steve Sterling <[email protected]> wrote:

> You're really knowledgable about this Damian!  How do you work around the
> challenges with multiple leads, will each lead require it's own circuit?
>
> Thanks,
> Steve
>
> On Sun, Sep 20, 2020, 1:17 PM Dami=C3=A1n Filo <[email protected]> wrote=
:
>
>> I am sorry for the spam, but in my previous e-mail I said: "any of those
>> changes you proposed are possible" - that is false. One change you
>> mentioned was to feed raw data onto GPIO pins of RPi. That will not work=
,
>> because what you need to do with the signal is to convert it from analog=
 to
>> digital data through ADC and RPi doesn't have an ADCs. You can avoid usi=
ng
>> ATmega microcontrollers, but you still would have to use some external c=
hip
>> with ADC functions. And then you would have to program your own firmware
>> and protocol, so you can use the data in applications running on RPi.
>> Though what you can do with RPi is to feed the data directly from ATmega
>> through native UART interface on RPi without the need for USB-UART chip.
>> But about that, I am not really sure about the signalling voltage mismat=
ch
>> 5V/3.3V. So it is still preferred to use a USB interface with UART bridg=
e
>> like CP2102.
>>
>> S pozdravom,
>> Dami=C3=A1n Filo
>>
>>
>> so 5. 9. 2020 o 21:49 Yonah Elorza <[email protected]> nap=C3=ADsal(a):
>>
>>> Hello!
>>>
>>> I'm a computer engineer interested in making some modifications to the
>>> OpenEEG circuit, and had a few questions, if anyone is available to ans=
wer
>>> them. I've read through all the documentation on the website, and have
>>> worked with the OpenEEG platform for a few years now, and wanted to see=
 if
>>> the following was possible:
>>>
>>> -Designing better noise cancelling to reduce commons noise, as well as
>>> noise between electrodes.
>>> -Integrating an FPGA into the design which acts as a hardware Fast
>>> Fourier Transform
>>> -Making the circuit modular enough that you can stack multiple together
>>> to have 4, 8, 16, etc. electrodes reading at the same time.
>>> -Long term: modifying the design of the circuit to work without the AT
>>> processor, instead having hardware control from the GPIO of a Raspberry=
 Pi,
>>> and all data being fed raw to either the GPIO or USB interface of the P=
i.
>>>
>>> If anyone has reasons this wouldn't be possible, or if you have
>>> suggestions for any of these changes, please let me know. I absolutely =
love
>>> this project, and would love to be able to contribute my own work to it=
.
>>>
>>> --
>>> Best Regards,
>>> Yonah Elorza
>>> Columbia School of Engineering | Class of 2018
>>> Computer Engineering
>>> Tel: ( <%28786%29%20205%20-%204304>305)-542-1735
>>> _______________________________________________
>>> Openeeg-list mailing list
>>> [email protected]
>>> https://lists.sourceforge.net/lists/listinfo/openeeg-list
>>> Go to the above address to change your
>>> subscription options, e.g unsubscribe.
>>>
>> _______________________________________________
>> Openeeg-list mailing list
>> [email protected]
>> https://lists.sourceforge.net/lists/listinfo/openeeg-list
>> Go to the above address to change your
>> subscription options, e.g unsubscribe.
>>
> _______________________________________________
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> subscription options, e.g unsubscribe.
>

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<div dir=3D"auto"><div><div dir=3D"auto">I am not, really... :D</div><div d=
ir=3D"auto">Can you please define &quot;leads&quot;? Do you mean channels?<=
/div><div dir=3D"auto">And what challenges?=C2=A0</div><div dir=3D"auto"><b=
r></div><div dir=3D"auto">OpenEEG is in default built as bipolar EEG. That =
means for each channel you need to connect two electrodes. The output is di=
fference of voltage between those two electrodes. But even with two electro=
des you won&#39;t need to make two amplfication circuits. The difference of=
 voltages is processed in the instrumentation amplifier (first amplifier) a=
nd then the one difference signal is amplified further, so it can be reliab=
ly converted to digital data. So you will need an amplification circuit (ca=
scade) for each channel (2 electrodes).</div><div dir=3D"auto">OpenEEG with=
 v2 protocol and baud rate 115200 can support up to 6 channels, although AT=
mega16 can support 8. If there is need for more channels, you would have to=
 rewrite the firmware and change the baud rate. But with that you would los=
e compatibility with software supporting OpenEEG (like BrainBay).</div><div=
 dir=3D"auto">I simply chose not to face those challenges and I stuck to th=
e specifications concerning OpenEEG compatibility. I use olimex v2 protocol=
 firmware with ATmega16L.=C2=A0</div><div dir=3D"auto"><br></div><br><br><d=
iv class=3D"gmail_quote"><div dir=3D"ltr" class=3D"gmail_attr">On Sun, Sep =
20, 2020, 23:18 Steve Sterling &lt;<a href=3D"mailto:[email protected]">ac=
[email protected]</a>&gt; wrote:<br></div><blockquote class=3D"gmail_quote" =
style=3D"margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><di=
v dir=3D"auto">You&#39;re really knowledgable about this Damian!=C2=A0 How =
do you work around the challenges with multiple leads, will each lead requi=
re it&#39;s own circuit?<div dir=3D"auto"><br></div><div dir=3D"auto">Thank=
s,</div><div dir=3D"auto">Steve</div></div><br><div class=3D"gmail_quote"><=
div dir=3D"ltr" class=3D"gmail_attr">On Sun, Sep 20, 2020, 1:17 PM Dami=C3=
=A1n Filo &lt;<a href=3D"mailto:[email protected]" target=3D"_blank" rel=
=3D"noreferrer">[email protected]</a>&gt; wrote:<br></div><blockquote clas=
s=3D"gmail_quote" style=3D"margin:0 0 0 .8ex;border-left:1px #ccc solid;pad=
ding-left:1ex"><div dir=3D"ltr"><div>I am sorry for the spam, but in my pre=
vious e-mail I said: &quot;any of those changes you proposed are possible&q=
uot; - that is false. One change you mentioned was to feed raw data onto GP=
IO pins of RPi. That will not work, because what you need to do with the si=
gnal is to convert it from analog to digital data through ADC and RPi doesn=
&#39;t have an ADCs. You can avoid using ATmega microcontrollers, but you s=
till would have to use some external chip with ADC functions. And then you =
would have to program your own firmware and protocol, so you can use the da=
ta in applications running on RPi.<br></div><div>Though what you can do wit=
h RPi is to feed the data directly from ATmega through native UART interfac=
e on RPi without the need for USB-UART chip. But about that, I am not reall=
y sure about the signalling voltage mismatch 5V/3.3V. So it is still prefer=
red to use a USB interface with UART bridge like CP2102.<br></div><div><br>=
</div><div><div><div dir=3D"ltr" data-smartmail=3D"gmail_signature"><div di=
r=3D"ltr"><div>S pozdravom,</div><div>Dami=C3=A1n Filo<br></div></div></div=
></div><br></div></div><br><div class=3D"gmail_quote"><div dir=3D"ltr" clas=
s=3D"gmail_attr">so 5. 9. 2020 o=C2=A021:49 Yonah Elorza &lt;<a href=3D"mai=
lto:[email protected]" rel=3D"noreferrer noreferrer" target=3D"_blank">yona=
[email protected]</a>&gt; nap=C3=ADsal(a):<br></div><blockquote class=3D"gmail_=
quote" style=3D"margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,=
204);padding-left:1ex"><div dir=3D"ltr"><div>Hello!</div><div><br></div><di=
v>I&#39;m a computer engineer interested in making some modifications to th=
e OpenEEG circuit, and had a few questions, if anyone is available to answe=
r them. I&#39;ve read through all the documentation on the website, and hav=
e worked with the OpenEEG platform for a few years now, and wanted to see i=
f the following was possible:</div><div><br></div><div>-Designing better no=
ise cancelling to reduce commons noise, as well as noise between electrodes=
.</div><div>-Integrating an FPGA into the design which acts as a hardware F=
ast Fourier Transform</div><div>-Making the circuit modular enough that you=
 can stack multiple together to have 4, 8, 16, etc. electrodes reading at t=
he same time.<br></div><div>-Long term: modifying the design of the circuit=
 to work without the AT processor, instead having hardware control from the=
 GPIO of a Raspberry Pi, and all data being fed raw to either the GPIO or U=
SB interface of the Pi. <br><br></div><div>If anyone has reasons this would=
n&#39;t be possible, or if you have suggestions for any of these changes, p=
lease let me know. I absolutely love this project, and would love to be abl=
e to contribute my own work to it.<br></div><div><br>-- <br><div dir=3D"ltr=
"><div dir=3D"ltr"><div><div dir=3D"ltr"><div dir=3D"ltr" style=3D"font-siz=
e:12.8px"><div>Best Regards,<br></div>Yonah Elorza<br></div><div dir=3D"ltr=
" style=3D"font-size:12.8px"><div style=3D"font-size:12.8px">Columbia Schoo=
l of Engineering | Class of 2018</div><div style=3D"font-size:12.8px">Compu=
ter Engineering</div><div style=3D"font-size:12.8px">Tel:=C2=A0<a href=3D"t=
el:%28786%29%20205%20-%204304" value=3D"+17862054304" style=3D"color:rgb(17=
,85,204)" rel=3D"noreferrer noreferrer" target=3D"_blank">(</a><span><span =
title=3D"Call with Google Voice">305)-542-1735</span></span></div></div></d=
iv></div></div></div></div></div>
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</blockquote></div>
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Openeeg-list mailing list<br>
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</blockquote></div>
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=3D"noreferrer">[email protected]</a><br>
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