Re: Discussion of EEG hardware, software, training protocols, NFB theory - for developers and users
Damián Filo <[email protected]> Tue, 27 Mar 2018 15:37:02 +0200
| Newsgroups | gmane.comp.science.openeeg.general |
|---|---|
| Message-ID | <CALPZnbHoV-Or3o0J5TFwRL=GXx-mvEj98XxcTHFCriWQJwHQgQ@mail.gmail.com> |
--===============2612093003198336760== Content-Type: multipart/alternative; boundary="00000000000058b3b6056864fc28" --00000000000058b3b6056864fc28 Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable Hi Raymond, You are right, I didn't change much. The INA128 I used was cheaper and even with better specs, than INA114 so I went for it. As you mentioned INA828 to be improved INA128 it should be better choice for newer designs. When I was ordering parts for my EEG (few months ago), the INA828 weren't released yet. You can do a bit of research if they are fully compatible for replacement of INA128. I looked and they are almost for half the price, that could be great. I think the olimex is using also INA114... https://www.olimex.com/Products/EEG/OpenEEG/EEG-SMT/resources/EEG-SMT-SCHEM= ATIC-REV-B.pdf About the documentation, you can try to google-translate it or just look at the images at the last pages, there is also alpha wave measurement, which I captured on myself. (eyes closed - eyes open) I work with dry electrodes as well and the sensitivity improvement is notable. Maybe in future I will rework my electrodes. As for now I left open the oppourtunity for experimenting by routing the unconnected remaining 4 channels onto the connector. Anyone can just make some experimental board for example with the before mentioned INA828. But yes, the electrodes are very important too. use of better materials, different opamps, shielding, better construction... There is so much to experiment with. My work is focused on connectivity and manufacturability rather than experimentation (which is also allowed). I wasn't designing whole new EEG, I just made an exceptional school-project. Using principles of OpenEEG. Best regards, Dami=C3=A1n Filo 2018-03-27 13:42 GMT+02:00 Raymond Chan <[email protected]>: > Hi Damian, > > Thank you. I am able to open and look at your schematics. > > > > (1) The only change I noticed is that you are using an INA128 op-amp. Are > there any other changes that you have made but I missed please? Your > documentation is in Slovak language which I do not understand. > > > > (2) The original Olimex board uses an INA116 op-amp. The extremely low > input bias current and guarded inputs of this op-amp enable the board to > work with passive electrodes. However, when active electrodes are used, > these merits are not relevant and the expensive INA116 becomes overkill. > Therefore, current Olimex board uses an INA114 op-amp which is much cheap= er > than the INA116. > > > > (3) From the characteristics on the data sheets, I do not see any > significant differences between the INA128 and INA114. Moreover, the INA1= 28 > has been superseded by the INA828. In TI=E2=80=99s own words, the INA828 = is the > second generation INA128. Therefore, I am curious as to what other change= s > you might have made in your design other than the use of the INA128 inste= ad > of the INA114. > > > > (4) Last and least, I am happy to share my work on the Olimex EEG board > too. Specifically, I work with dry electrodes. By replacing the TL062 in > Olimex=E2=80=99s active electrode with a LMP7702 (which is pin-to-pin com= patible > with the TL062), I am able to achieved a 6 dB increase in sensitivity. > > > > Raymond Chan > > > On Mon, Mar 26, 2018 at 8:04 PM, Dami=C3=A1n Filo <[email protected]> wr= ote: > >> Of course, it is made in Eagle. >> >> >> 2018-03-26 13:45 GMT+02:00 Raymond Chan <[email protected]>: >> >>> Hi Damian, >>> >>> I am also working on improving the EEG-SMT boards by Olimex. I would >>> like to look at your work. Which software would open your schematics >>> diagram please? Thank you. >>> >>> Raymond Chan >>> >> >> >> >> -- >> Dami=C3=A1n Filo >> > > > > -- > Raymond > --00000000000058b3b6056864fc28 Content-Type: text/html; charset="UTF-8" Content-Transfer-Encoding: quoted-printable <div dir=3D"ltr"><div><div><div><div><div>Hi Raymond,<br></div>You are righ= t, I didn't change much. The INA128 I used was cheaper and even with be= tter specs, than INA114 so I went for it. As you mentioned INA828 to be imp= roved INA128 it should be better choice for newer designs. When I was order= ing parts for my EEG (few months ago), the INA828 weren't released yet.= You can do a bit of research if they are fully compatible for replacement = of INA128. I looked and they are almost for half the price, that could be g= reat.<br><br></div>I think the olimex is using also INA114... <a href=3D"ht= tps://www.olimex.com/Products/EEG/OpenEEG/EEG-SMT/resources/EEG-SMT-SCHEMAT= IC-REV-B.pdf">https://www.olimex.com/Products/EEG/OpenEEG/EEG-SMT/resources= /EEG-SMT-SCHEMATIC-REV-B.pdf</a> <br><br></div>About the documentation, you= can try to google-translate it or just look at the images at the last page= s, there is also alpha wave measurement, which I captured on myself. (eyes = closed - eyes open)<br><br></div>I work with dry electrodes as well and the= sensitivity improvement is notable. Maybe in future I will rework my elect= rodes. As for now I left open the oppourtunity for experimenting by routing= the unconnected remaining 4 channels onto the connector. Anyone can just m= ake some experimental board for example with the before mentioned INA828. B= ut yes, the electrodes are very important too. use of better materials, dif= ferent opamps, shielding, better construction... There is so much to experi= ment with.<br><br></div><div>My work is focused on connectivity and manufac= turability rather than experimentation (which is also allowed). I wasn'= t designing whole new EEG, I just made an exceptional school-project. Using= principles of OpenEEG.<br><br></div><div>Best regards,<br></div><div>Dami= =C3=A1n Filo<br></div><div class=3D"gmail_extra"><br><div class=3D"gmail_qu= ote">2018-03-27 13:42 GMT+02:00 Raymond Chan <span dir=3D"ltr"><<a href= =3D"mailto:[email protected]" target=3D"_blank">raymondhkgchan@gmail= .com</a>></span>:<br><blockquote class=3D"gmail_quote" style=3D"margin:0= 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><div dir=3D"ltr"> <p class=3D"MsoNormal" style=3D"margin:0in 0in 0.0001pt;font-size:12pt;font= -family:"Times New Roman",serif"><span style=3D"font-size:11pt">H= i Damian,<span></span></span></p> <p class=3D"MsoNormal" style=3D"margin:0in 0in 0.0001pt;font-size:12pt;font= -family:"Times New Roman",serif"><span style=3D"font-size:11pt">T= hank you. I am able to open and look at your schematics. <span></span></span></p= > <p class=3D"MsoNormal" style=3D"margin:0in 0in 0.0001pt;font-size:12pt;font= -family:"Times New Roman",serif"><span style=3D"font-size:11pt"><= span>=C2=A0</span></span></p> <p class=3D"MsoNormal" style=3D"margin:0in 0in 0.0001pt;font-size:12pt;font= -family:"Times New Roman",serif"><span style=3D"font-size:11pt">(= 1) The only change I noticed is that you are using an INA128 op-amp. Are there= any other changes that you have made but I missed please? Your documentation is= in Slovak language which I do not understand.<span></span></span></p> <p class=3D"MsoNormal" style=3D"margin:0in 0in 0.0001pt;font-size:12pt;font= -family:"Times New Roman",serif"><span style=3D"font-size:11pt"><= span>=C2=A0</span></span></p> <p class=3D"MsoNormal" style=3D"margin:0in 0in 0.0001pt;font-size:12pt;font= -family:"Times New Roman",serif"><span style=3D"font-size:11pt">(= 2) The original Olimex board uses an INA116 op-amp. The extremely low input bi= as current and guarded inputs of this op-amp enable the board to work with pas= sive electrodes. However, when active electrodes are used, these merits are not relevant and the expensive INA116 becomes overkill. Therefore, current Olim= ex board uses an INA114 op-amp which is much cheaper than the INA116.<span></s= pan></span></p> <p class=3D"MsoNormal" style=3D"margin:0in 0in 0.0001pt;font-size:12pt;font= -family:"Times New Roman",serif"><span style=3D"font-size:11pt"><= span>=C2=A0</span></span></p> <p class=3D"MsoNormal" style=3D"margin:0in 0in 0.0001pt;font-size:12pt;font= -family:"Times New Roman",serif"><span style=3D"font-size:11pt">(= 3) From the characteristics on the data sheets, I do not see any significant differences between the INA128 and INA114. Moreover, the INA128 has been su= perseded by the INA828. In TI=E2=80=99s own words, the INA828 is the second generati= on INA128. Therefore, I am curious as to what other changes you might have made in your design ot= her than the use of the INA128 instead of the INA114.<span></span></span></p> <p class=3D"MsoNormal" style=3D"margin:0in 0in 0.0001pt;font-size:12pt;font= -family:"Times New Roman",serif"><span style=3D"font-size:11pt"><= span>=C2=A0</span></span></p> <p class=3D"MsoNormal" style=3D"margin:0in 0in 0.0001pt;font-size:12pt;font= -family:"Times New Roman",serif"><span style=3D"font-size:11pt">(= 4) Last and least, I am happy to share my work on the Olimex EEG board too. Sp= ecifically, I work with dry electrodes. By replacing the TL062 in Olimex=E2=80=99s acti= ve electrode with a LMP7702 (which is pin-to-pin compatible with the TL062), I am able t= o achieved a 6 dB increase in sensitivity.=C2=A0<span></span></span></p> <p class=3D"MsoNormal" style=3D"margin:0in 0in 0.0001pt;font-size:12pt;font= -family:"Times New Roman",serif"><span style=3D"font-size:11pt"><= span>=C2=A0</span></span></p> <p class=3D"MsoNormal" style=3D"margin:0in 0in 0.0001pt;font-size:12pt;font= -family:"Times New Roman",serif"><span style=3D"font-size:11pt">R= aymond Chan<span></span></span></p> <br></div><div class=3D"gmail_extra"><div><div class=3D"h5"><br><div class= =3D"gmail_quote">On Mon, Mar 26, 2018 at 8:04 PM, Dami=C3=A1n Filo <span di= r=3D"ltr"><<a href=3D"mailto:[email protected]" target=3D"_blank">nogai= [email protected]</a>></span> wrote:<br><blockquote class=3D"gmail_quote" st= yle=3D"margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><div = dir=3D"ltr">Of course, it is made in Eagle.<br><br></div><div class=3D"gmai= l_extra"><div><div class=3D"m_-1347819927497394723h5"><br><div class=3D"gma= il_quote">2018-03-26 13:45 GMT+02:00 Raymond Chan <span dir=3D"ltr"><<a = href=3D"mailto:[email protected]" target=3D"_blank">raymondhkgchan@g= mail.com</a>></span>:<br><blockquote class=3D"gmail_quote" style=3D"marg= in:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><div dir=3D"ltr"= > <p class=3D"MsoNormal" style=3D"margin:0in 0in 0.0001pt;font-size:12pt;font= -family:"Times New Roman",serif"><span style=3D"font-size:11pt;co= lor:rgb(34,34,34);background:white">Hi Damian,</span><span style=3D"font-size:11pt"><span></span></span></p> <p class=3D"MsoNormal" style=3D"margin:0in 0in 0.0001pt;font-size:12pt;font= -family:"Times New Roman",serif"><span style=3D"font-size:11pt;co= lor:rgb(34,34,34)">I am also working on improving the <span style=3D"background:white">EEG-SMT boards by= Olimex</span>. I would like to look at your work. </span>Which software would open your schematics diagram please? Thank you.<span class=3D"m_-1347819927497394723m= _-7671782533370612510HOEnZb"><font color=3D"#888888"><span></span></font></= span></p><span class=3D"m_-1347819927497394723m_-7671782533370612510HOEnZb"= ><font color=3D"#888888"> <p class=3D"MsoNormal" style=3D"margin:0in 0in 0.0001pt;font-size:12pt;font= -family:"Times New Roman",serif"><span style=3D"font-size:11pt;co= lor:rgb(34,34,34)">Raymond Chan<span></span></span></p> </font></span></div> </blockquote></div><br><br clear=3D"all"><br></div></div><span class=3D"m_-= 1347819927497394723HOEnZb"><font color=3D"#888888">-- <br><div class=3D"m_-= 1347819927497394723m_-7671782533370612510gmail_signature" data-smartmail=3D= "gmail_signature">Dami=C3=A1n Filo</div> </font></span></div> </blockquote></div><br><br clear=3D"all"><div><br></div></div></div><span c= lass=3D"HOEnZb"><font color=3D"#888888">-- <br><div class=3D"m_-13478199274= 97394723gmail_signature" data-smartmail=3D"gmail_signature"><div dir=3D"ltr= ">Raymond</div></div> </font></span></div> </blockquote></div><br> </div></div> --00000000000058b3b6056864fc28-- --===============2612093003198336760== Content-Type: text/plain; charset="us-ascii" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit Content-Disposition: inline ------------------------------------------------------------------------------ Check out the vibrant tech community on one of the world's most engaging tech sites, Slashdot.org! http://sdm.link/slashdot --===============2612093003198336760== Content-Type: text/plain; charset="us-ascii" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit Content-Disposition: inline