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Re: [Openeeg-list] OpenEEG Questions
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From: Greg F. <mf...@gm...> - 2020-09-24 23:17:37
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Hi Jordan, Try this link to modify your subscription https://lists.sourceforge.net/lists/listinfo/openeeg-list Kind regards, Greg Feneis (Pixel 3) On Thu, Sep 24, 2020, 13:15 Jordan <joc...@gm...> wrote: > Can you remove me from your mailing list? > > *Jordan Harris, Ph.D, LPC, LMFT* > > Trauma Therapist and Couples Counselor > > https://medium.com/@informedsimplicity > > Cell: (410) 300 3461 > > > > > > On Wed, Sep 23, 2020 at 2:43 PM Yonah Elorza <yo...@gm...> wrote: > >> Hello all, >> >> Thank you all so much for your great advice. I'm starting prototyping >> with one channel for now, to test my schematics and ICs, as well as my >> control mechanisms. If I make any headway with my changes, I'll make sure >> to reach out to you all and give you an update! >> >> On Mon, Sep 21, 2020 at 5:44 AM Blago Gmail <don...@gm...> wrote: >> >>> Hello Yonah, >>> >>> Your idea for developing upgraded hardware for OpenEEG is definitely >>> good! >>> >>> I wonder how many users feel "performance constrained" with current >>> version? >>> >>> Here are you points: >>> >>> -Designing better noise cancelling to reduce commons noise, >>> >>> as well as noise between electrodes. >>> You can gain significant improvements over signal to noise ratio if you >>> "integrate" the signal processing chain down to the ADC - the so called >>> Analog Front-End (AFE). What I mean under integration is to choose from >>> available options multi-channel AFE implemented as integrated circuit >>> (ASIC) - Texas-instruments, Analog-devices, Linear.... Those AFE chips >>> are coming with TIA (first amplification, in Damian's terms) and PGA >>> (second amplification) amplifiers + different type (single-ended or >>> differential) and resolution, ADC inside. All of them requires some kind >>> of external digital control + reading out converted data samples (they >>> don't memory buffers or storage place inside) >>> >>> >>> -Integrating an FPGA into the design which acts as a >>> >>> hardware Fast Fourier Transform >>> I think you are underestimating the FPGAs. Despite the good use for >>> signal processing, FPGA are good for implementing timing engines (the >>> control signals needs to drive properly your AFE circuit). >>> >>> Imagine you are picking up an FPGA such as ZYNQ, who comes with dual >>> core ARM processor inside... you are pretty much done with the >>> configurable hardware you want. The firmware whiten for the ATMega >>> should be ported to ARM but this will come with reward to have much more >>> powerful processing unit. The FPGA fabric can be used for signal >>> processing and controlling the external AFE. As you will end-up with >>> good amount of data samples, better consider USB3/USB2 as interface with >>> the PC. >>> >>> >>> -Making the circuit modular enough that you can stack >>> >>> multiple together to have 4, 8, 16, etc. electrodes reading >>> >>> at the same time. >>> If you go the FPGA way, you will have ability to have reconfiguration on >>> PCB and IC levels. >>> >>> >>> >>> -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 Pi. >>> Raspberry Pi is good platform but OpenEEG is too hardware specific that >>> I am afraid that platforms as Raspberry Pi or Begalbone or Arduino are >>> too generic for this project. >>> >>> Kind regards, >>> >>> Blagomir Donchev >>> >>> >>> >>> >>> >>> On 20/09/2020 23:46, Damián Filo wrote: >>> > 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 <acu...@gm... >>> > <mailto:acu...@gm...>> 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 Damián Filo <nog...@gm... >>> > <mailto:nog...@gm...>> 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 using ATmega >>> > microcontrollers, but you still 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 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 mismatch 5V/3.3V. So it is still >>> > preferred to use a USB interface with UART bridge like CP2102. >>> > >>> > S pozdravom, >>> > Damián Filo >>> > >>> > >>> > so 5. 9. 2020 o 21:49 Yonah Elorza <yo...@gm... >>> > <mailto:yo...@gm...>> napísal(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 answer 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 Pi. >>> > >>> > 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: ( <tel:%28786%29%20205%20-%204304>305)-542-1735 >>> > _______________________________________________ >>> > Openeeg-list mailing list >>> > Ope...@li... >>> > <mailto:Ope...@li...> >>> > 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 >>> > Ope...@li... >>> > <mailto:Ope...@li...> >>> > 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 >>> > Ope...@li... >>> > <mailto:Ope...@li...> >>> > 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 >>> > Ope...@li... >>> > 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 >>> Ope...@li... >>> https://lists.sourceforge.net/lists/listinfo/openeeg-list >>> Go to the above address to change your >>> subscription options, e.g unsubscribe. >>> >> >> >> -- >> 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 >> Ope...@li... >> 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 > Ope...@li... > https://lists.sourceforge.net/lists/listinfo/openeeg-list > Go to the above address to change your > subscription options, e.g unsubscribe. > |
