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modular eeg work report

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  • Chris
    hallo Jörg ! falls du am wochenende auf meine mail geantwortet hast: bitte nochmal schicken, mein email-account hat samstag und sonntag nicht funktioniert.
    Message 1 of 9 , Jul 9, 2002
      hallo Jörg !

      falls du am wochenende auf meine mail geantwortet hast: bitte nochmal schicken, mein
      email-account hat samstag und sonntag nicht funktioniert.

      vielen dank,
      chris.
    • Dave Fisher
      This is the output from the preliminary version of the BioDevice library. Right now the only device implemented is Thought Technologies ProComp+. To really
      Message 2 of 9 , Jul 9, 2002
        This is the output from the preliminary version of the "BioDevice" library.
        Right now the only device implemented is Thought Technologies ProComp+. To
        really flesh out the library and make sure the design "holds water," we'll need
        other devices implemented -- ModularEEG, TinyEEG, BrainMaster, or otherwise.
        Any takers, please raise your hand.

        Here's the basic flow with comments:

        22:16:22: Debug: Creating BioSysInfo system object
        22:16:22: Debug: Config: default system file path: ./
        22:16:22: Debug: Config: client data file path = ~/biomon
        22:16:22: Debug: Config: Creating table of BioUnits (8 items)
        22:16:22: Debug: 1: NONE
        22:16:22: Debug: 2: MICROVOLTS
        22:16:22: Debug: 3: CELCIUS
        22:16:22: Debug: 4: FAHRENHEIT
        22:16:22: Debug: 5: PERCENTAGE
        22:16:22: Debug: 6: MICROMHO
        22:16:22: Debug: 7: KILOOHM
        22:16:22: Debug: 8: HERTZ
        22:16:22: Debug: Config: Creating table of BioDataTypes (9 items)
        22:16:22: Debug: 1: NONE
        22:16:22: Debug: 2: EEG
        22:16:22: Debug: 3: GSR
        22:16:22: Debug: 4: EKG
        22:16:22: Debug: 5: TEMP
        22:16:22: Debug: 6: BVP
        22:16:22: Debug: 7: RESP
        22:16:22: Debug: 8: FFT
        22:16:22: Debug: 9: BATTERY
        22:16:22: Debug: Config: Adding to device list: ProComp (Thought Technologies
        ProComp+)
        22:16:22: Debug: Loading BioDevice info from configuration file
        (key=/biolib/device-ProComp)
        22:16:22: Debug: Device ProComp: Adding modality (undefined type) ((undefined
        unit type))
        22:16:22: Debug: Device ProComp: Adding modality EEG (microvolts)
        22:16:22: Debug: Device ProComp: Adding modality SC/GSR (micromho)
        22:16:22: Debug: Device ProComp: Adding modality EKG (microvolts)
        22:16:22: Debug: Device ProComp: Adding modality HR/BVP (Percentage (0..1))
        22:16:22: Debug: Device ProComp: Adding modality Respiration (Percentage
        (0..1))
        22:16:22: Debug: Device ProComp: Adding modality Temperature (Celcius)
        22:16:22: Debug: Device ProComp: Adding modality Temperature (Fahrenheit)
        22:16:22: Debug: Device ProComp: Adding modality Battery Level (microvolts)
        22:16:22: Debug: Device ProComp: Adding channel Channel-A (tied to modality
        EEG-microvolts)
        22:16:22: Debug: Device ProComp: Adding channel Channel-B (tied to modality
        EEG-microvolts)
        22:16:22: Debug: Device ProComp: Adding channel Channel-C (tied to modality
        NONE-(undefined unit type))
        22:16:22: Debug: Device ProComp: Adding channel Channel-D (tied to modality
        NONE-(undefined unit type))
        22:16:22: Debug: Device ProComp: Adding channel Channel-E (tied to modality
        NONE-(undefined unit type))
        22:16:22: Debug: Device ProComp: Adding channel Channel-F (tied to modality
        NONE-(undefined unit type))
        22:16:22: Debug: Device ProComp: Adding channel Channel-G (tied to modality
        NONE-(undefined unit type))
        22:16:22: Debug: Device ProComp: Adding channel Channel-H (tied to modality
        NONE-(undefined unit type))
        22:16:22: Main Started.
        22:16:22: Debug: BioDevice Information for device ProComp (Thought Technologies
        ProComp+)
        22:16:22: Debug: Available modalities: 9
        22:16:22: Debug: 1: NONE ((undefined type), (undefined unit type))
        22:16:22: Debug: 2: EEG (EEG, microvolts)
        22:16:22: Debug: 3: GSR (SC/GSR, micromho)
        22:16:22: Debug: 4: EKG (EKG, microvolts)
        22:16:22: Debug: 5: BVP (HR/BVP, Percentage (0..1))
        22:16:22: Debug: 6: RESP (Respiration, Percentage (0..1))
        22:16:22: Debug: 7: TEMP (Temperature, Celcius)
        22:16:22: Debug: 8: TEMP (Temperature, Fahrenheit)
        22:16:22: Debug: 9: BATTERY (Battery Level, microvolts)
        22:16:22: Debug: Default channels: 8
        22:16:22: Debug: 1: Channel-A using modality EEG
        22:16:22: Debug: 2: Channel-B using modality EEG
        22:16:22: Debug: 3: Channel-C using modality NONE
        22:16:22: Debug: 4: Channel-D using modality NONE
        22:16:22: Debug: 5: Channel-E using modality NONE
        22:16:22: Debug: 6: Channel-F using modality NONE
        22:16:22: Debug: 7: Channel-G using modality NONE
        22:16:22: Debug: 8: Channel-H using modality NONE
        22:16:22: Debug: BioNode: Creating node object 'Thought Technologies ProComp+'
        22:16:22: Debug: BioNode: Creating output channel 'Channel-A' (type=EEG)
        22:16:22: Debug: BioNode: Creating output channel 'Channel-B' (type=EEG)
        22:16:22: Debug: BioNode: Creating output channel 'Channel-C' (type=(undefined
        type))
        22:16:22: Debug: BioNode: Creating output channel 'Channel-D' (type=(undefined
        type))
        22:16:22: Debug: BioNode: Creating output channel 'Channel-E' (type=(undefined
        type))
        22:16:22: Debug: BioNode: Creating output channel 'Channel-F' (type=(undefined
        type))
        22:16:22: Debug: BioNode: Creating output channel 'Channel-G' (type=(undefined
        type))
        22:16:22: Debug: BioNode: Creating output channel 'Channel-H' (type=(undefined
        type))
        22:16:22: Debug: BioNode: Adding node 'Thought Technologies ProComp+' - address
        = 0x806e278

        All the above is default information read from the configuration file. Below
        is where I actually configure the device the way I wanted it -- which is to
        associate EEG modalities with Channels A & B and GSR with Channel C. Most
        devices will not need this step, as they will have fixed modalities.

        22:16:22: Debug: Serial port configured and ready.
        22:16:22: Debug: BioNode: Thought Technologies ProComp+
        22:16:22: Debug: Input Channels = 0
        22:16:22: Debug: Output Channels = 8
        22:16:22: Debug: Output Channel 1 : Channel-A (EEG)
        22:16:22: Debug: Output Channel 2 : Channel-B (EEG)
        22:16:22: Debug: Output Channel 3 : Channel-C (SC/GSR)
        22:16:22: Debug: Output Channel 4 : Channel-D ((undefined type))
        22:16:22: Debug: Output Channel 5 : Channel-E ((undefined type))
        22:16:22: Debug: Output Channel 6 : Channel-F ((undefined type))
        22:16:22: Debug: Output Channel 7 : Channel-G ((undefined type))
        22:16:22: Debug: Output Channel 8 : Channel-H ((undefined type))
        22:16:22: Debug: BioNode: Creating node object 'BioData Monitor'
        22:16:22: Debug: BioNode: Adding node 'BioData Monitor' - address = 0xbffff968

        The "BioNode" method of handling the data streams is Jim P's brainchild. While
        I have implemented it using some STL conventions (vectors and iterators), I am
        thinking that he is right in that it can be made much more efficient (and
        probably should be done considering the time critical nature of this part of
        the system) by using straight C code.

        22:16:22: Debug: Data Processing Network:
        22:16:22: Debug: Node count = 2
        22:16:22: Debug: BioNode: Thought Technologies ProComp+
        22:16:22: Debug: Input Channels = 0
        22:16:22: Debug: Output Channels = 8
        22:16:22: Debug: Output Channel 1 : Channel-A (EEG)
        22:16:22: Debug: Output Channel 2 : Channel-B (EEG)
        22:16:22: Debug: Output Channel 3 : Channel-C (SC/GSR)
        22:16:22: Debug: Output Channel 4 : Channel-D ((undefined type))
        22:16:22: Debug: Output Channel 5 : Channel-E ((undefined type))
        22:16:22: Debug: Output Channel 6 : Channel-F ((undefined type))
        22:16:22: Debug: Output Channel 7 : Channel-G ((undefined type))
        22:16:22: Debug: Output Channel 8 : Channel-H ((undefined type))
        22:16:22: Debug: BioNode: BioData Monitor
        22:16:22: Debug: Input Channels = 3
        22:16:22: Debug: Output Channels = 0
        22:16:22: Debug: Input Channel 1 : Channel-A
        22:16:22: Debug: Input Channel 2 : Channel-B
        22:16:22: Debug: Input Channel 3 : Channel-C
        22:16:22: Debug: Got sync!

        And here comes the data from the monitoring class. Notice that Channel-C is at
        a different sample rate than Channels A & B. The ProComp generates 256Hz for A
        & B, while Channels C-H are 32Hz. I need to change the message a bit because
        it says "Error: No value..." which is really not an error at all. The data
        simply comes through the data processing node network at different rates.

        BTW.... the EEG electrodes were not connected to my head, which is good sign
        because if you look at the numbers, you might truly wonder if it is safe for me
        to be working with electronic equipment at all. ;-) The GSR are real values,
        however, as I connected those to my index and middle finger.

        22:16:22: ProComp Channel-A: EEG sample value = 4.3075 uV
        22:16:22: ProComp Channel-B: EEG sample value = 4.3074 uV
        22:16:22: ProComp Channel-C: GSR sample value = 0.0000 mo
        22:16:22: ProComp Channel-A: EEG sample value = 29.4685 uV
        22:16:22: ProComp Channel-B: EEG sample value = 45.2452 uV
        22:16:22: Error: No value from Channel 2 (Channel-C)
        22:16:22: ProComp Channel-A: EEG sample value = 222.4730 uV
        22:16:22: ProComp Channel-B: EEG sample value = 84.7914 uV
        22:16:22: ProComp Channel-C: GSR sample value = 3.9053 mo
        22:16:22: ProComp Channel-A: EEG sample value = 193.8386 uV
        22:16:23: ProComp Channel-B: EEG sample value = 284.6070 uV
        22:16:23: Error: No value from Channel 2 (Channel-C)
        22:16:23: ProComp Channel-A: EEG sample value = 54.4194 uV
        22:16:23: ProComp Channel-B: EEG sample value = 284.6070 uV
        22:16:23: Error: No value from Channel 2 (Channel-C)
        22:16:23: ProComp Channel-A: EEG sample value = 53.3769 uV
        22:16:23: ProComp Channel-B: EEG sample value = 97.9271 uV
        22:16:23: Error: No value from Channel 2 (Channel-C)
        22:16:23: ProComp Channel-A: EEG sample value = 134.9711 uV
        22:16:23: ProComp Channel-B: EEG sample value = 34.8896 uV
        22:16:23: Error: No value from Channel 2 (Channel-C)
        22:16:23: ProComp Channel-A: EEG sample value = 152.1379 uV
        22:16:23: ProComp Channel-B: EEG sample value = 274.8769 uV
        22:16:23: Error: No value from Channel 2 (Channel-C)
        22:16:23: ProComp Channel-A: EEG sample value = 134.3456 uV
        22:16:23: ProComp Channel-B: EEG sample value = 284.6070 uV
        22:16:23: Error: No value from Channel 2 (Channel-C)
        22:16:23: ProComp Channel-A: EEG sample value = 111.9663 uV
        22:16:23: ProComp Channel-B: EEG sample value = 166.6637 uV
        22:16:23: Error: No value from Channel 2 (Channel-C)
        22:16:23: ProComp Channel-A: EEG sample value = 67.4161 uV
        22:16:23: ProComp Channel-B: EEG sample value = 17.8618 uV
        22:16:23: ProComp Channel-C: GSR sample value = 3.9053 mo
        22:16:23: ProComp Channel-A: EEG sample value = 78.3277 uV
        22:16:23: ProComp Channel-B: EEG sample value = 195.9236 uV
        22:16:23: Error: No value from Channel 2 (Channel-C)
        22:16:23: ProComp Channel-A: EEG sample value = 186.7495 uV
        22:16:23: ProComp Channel-B: EEG sample value = 284.6070 uV
        22:16:23: Error: No value from Channel 2 (Channel-C)
        22:16:23: ProComp Channel-A: EEG sample value = 196.7576 uV
        22:16:23: ProComp Channel-B: EEG sample value = 232.3422 uV
        22:16:23: Error: No value from Channel 2 (Channel-C)
        22:16:23: ProComp Channel-A: EEG sample value = 33.3605 uV
        22:16:23: ProComp Channel-B: EEG sample value = 28.4955 uV
        22:16:23: Error: No value from Channel 2 (Channel-C)
        22:16:23: ProComp Channel-A: EEG sample value = 271.3323 uV
        22:16:23: ProComp Channel-B: EEG sample value = 119.1944 uV
        22:16:23: Error: No value from Channel 2 (Channel-C)
        22:16:23: ProComp Channel-A: EEG sample value = 201.3447 uV
        22:16:23: ProComp Channel-B: EEG sample value = 284.6070 uV
        22:16:23: Error: No value from Channel 2 (Channel-C)
        22:16:23: ProComp Channel-A: EEG sample value = 7.2976 uV
        22:16:23: ProComp Channel-B: EEG sample value = 284.6070 uV
        22:16:23: Error: No value from Channel 2 (Channel-C)
        22:16:23: ProComp Channel-A: EEG sample value = 37.3221 uV
        22:16:23: ProComp Channel-B: EEG sample value = 70.2656 uV
        22:16:23: ProComp Channel-C: GSR sample value = 3.9003 mo
        22:16:23: ProComp Channel-A: EEG sample value = 176.9498 uV
        22:16:23: ProComp Channel-B: EEG sample value = 56.7824 uV
        22:16:23: Error: No value from Channel 2 (Channel-C)
        22:16:23: ProComp Channel-A: EEG sample value = 177.2973 uV
        22:16:23: ProComp Channel-B: EEG sample value = 284.6070 uV
        22:16:23: Error: No value from Channel 2 (Channel-C)
        22:16:23: ProComp Channel-A: EEG sample value = 96.4675 uV
        22:16:23: ProComp Channel-B: EEG sample value = 284.6070 uV
        22:16:23: Error: No value from Channel 2 (Channel-C)
        22:16:23: ProComp Channel-A: EEG sample value = 78.3277 uV
        22:16:23: ProComp Channel-B: EEG sample value = 129.3416 uV
        22:16:23: Error: No value from Channel 2 (Channel-C)
        22:16:23: ProComp Channel-A: EEG sample value = 97.8576 uV
        22:16:23: ProComp Channel-B: EEG sample value = 20.7113 uV
        22:16:23: Error: No value from Channel 2 (Channel-C)
        22:16:23: ProComp Channel-A: EEG sample value = 119.2639 uV
        22:16:23: ProComp Channel-B: EEG sample value = 236.5818 uV
        22:16:23: Error: No value from Channel 2 (Channel-C)
        22:16:23: ProComp Channel-A: EEG sample value = 164.9261 uV
        22:16:23: ProComp Channel-B: EEG sample value = 284.6070 uV
        22:16:23: Error: No value from Channel 2 (Channel-C)
        22:16:23: ProComp Channel-A: EEG sample value = 152.6244 uV
        22:16:23: ProComp Channel-B: EEG sample value = 202.8042 uV
        22:16:23: ProComp Channel-C: GSR sample value = 3.9003 mo
        22:16:23: ProComp Channel-A: EEG sample value = 46.0792 uV
        22:16:23: ProComp Channel-B: EEG sample value = 22.2404 uV
        22:16:23: Error: No value from Channel 2 (Channel-C)
        22:16:23: ProComp Channel-A: EEG sample value = 34.3335 uV
        22:16:23: ProComp Channel-B: EEG sample value = 157.7675 uV
        22:16:23: Error: No value from Channel 2 (Channel-C)
        22:16:23: ProComp Channel-A: EEG sample value = 199.3292 uV
        22:16:23: ProComp Channel-B: EEG sample value = 284.6070 uV
        22:16:23: Error: No value from Channel 2 (Channel-C)
        22:16:23: ProComp Channel-A: EEG sample value = 244.1574 uV
        22:16:23: ProComp Channel-B: EEG sample value = 265.9807 uV
        22:16:23: Error: No value from Channel 2 (Channel-C)
        22:16:23: ProComp Channel-A: EEG sample value = 30.7195 uV
        22:16:23: ProComp Channel-B: EEG sample value = 51.0833 uV
        22:16:23: Error: No value from Channel 2 (Channel-C)
        22:16:23: ProComp Channel-A: EEG sample value = 224.2801 uV
        22:16:23: ProComp Channel-B: EEG sample value = 88.3359 uV
        22:16:23: Error: No value from Channel 2 (Channel-C)
        22:16:23: ProComp Channel-A: EEG sample value = 194.8116 uV
        22:16:23: ProComp Channel-B: EEG sample value = 284.6070 uV
        22:16:23: Error: No value from Channel 2 (Channel-C)
        22:16:23: ProComp Channel-A: EEG sample value = 54.9754 uV
        22:16:23: ProComp Channel-B: EEG sample value = 284.6070 uV
        22:16:23: ProComp Channel-C: GSR sample value = 3.9003 mo

        [snip -- and so on...]

        22:16:26: ProComp Channel-A: EEG sample value = 81.4553 uV
        22:16:26: ProComp Channel-B: EEG sample value = 284.6070 uV
        22:16:26: Error: No value from Channel 2 (Channel-C)
        22:16:26: ProComp Channel-A: EEG sample value = 68.3196 uV
        22:16:26: ProComp Channel-B: EEG sample value = 113.4258 uV
        22:16:26: ProComp Channel-C: GSR sample value = 3.9053 mo
        22:16:26: ProComp Channel-A: EEG sample value = 111.7578 uV
        22:16:26: ProComp Channel-B: EEG sample value = 22.2404 uV
        22:16:26: Error: No value from Channel 2 (Channel-C)
        22:16:26: ProComp Channel-A: EEG sample value = 133.6506 uV
        22:16:26: ProComp Channel-B: EEG sample value = 249.6480 uV
        22:16:26: Error: No value from Channel 2 (Channel-C)

        After running for a few seconds, I terminate the program and cleanup ensues.

        22:16:26: Debug: Total number of read errors on device 'ProComp' : 0
        22:16:26: Debug: BioNode: Removing node 'Thought Technologies ProComp+' from
        the network
        22:16:26: Debug: BioNode: destroying node object 'Thought Technologies
        ProComp+'
        22:16:26: Debug: BioNode: Removing output channel 'Channel-A' from node
        'Thought Technologies ProComp+'
        22:16:26: Debug: BioNode: Removing output channel 'Channel-B' from node
        'Thought Technologies ProComp+'
        22:16:26: Debug: BioNode: Removing output channel 'Channel-C' from node
        'Thought Technologies ProComp+'
        22:16:26: Debug: BioNode: Removing output channel 'Channel-D' from node
        'Thought Technologies ProComp+'
        22:16:26: Debug: BioNode: Removing output channel 'Channel-E' from node
        'Thought Technologies ProComp+'
        22:16:26: Debug: BioNode: Removing output channel 'Channel-F' from node
        'Thought Technologies ProComp+'
        22:16:26: Debug: BioNode: Removing output channel 'Channel-G' from node
        'Thought Technologies ProComp+'
        22:16:26: Debug: BioNode: Removing output channel 'Channel-H' from node
        'Thought Technologies ProComp+'
        22:16:27: Debug: Destroying MonitorData object
        22:16:27: Debug: BioNode: destroying node object 'BioData Monitor'
        22:16:27: Debug: BioNode: Removing InputChannel '(not defined)' from node
        'BioData Monitor'
        22:16:27: Debug: BioNode: Removing InputChannel '(not defined)' from node
        'BioData Monitor'
        22:16:27: Debug: BioNode: Removing InputChannel '(not defined)' from node
        'BioData Monitor'
        22:16:27: Main Ended.

        That's it. If you have any questions, let me know.

        Dave.
      • Chris
        Hi all members of the openEEG - Projekt ! This is my fisrt hello to the group, my name is Chris, i m from Austria (Vienna). I like working with the
        Message 3 of 9 , Jul 10, 2002
          Hi all members of the openEEG - Projekt !

          This is my fisrt hello to the group, my name is Chris, i'm from Austria
          (Vienna). I like working with the possibilities of biofeedback for a
          several years now, I built some installations (like a brain-driven
          car-racing-game, or the ironic 'brain-washing machine', which translates
          brainwaves into washing-sounds) to bring this technology more to the
          public. My engeneering comes more from the software-side, I have to
          describe my knowledge about amplifier-hardware as 'tiny'. I found the
          openEEG-project and the mailinglist about 3 months ago, searching for an
          eeg-concept that I could build with my home-grown hardware-skills. ..
          that was really a happy click!!
          I decided to manufacure the modular-eeg - design by Jörg, it seemed
          optimal for my needs and there was best documentation for this project
          at that time (april).
          After the downloads (eagle-cad, avr-gcc, SP12), printouts, PCB,
          orderings (I got most of the parts here in vienna, 1 capacitor 0,3u and
          4 'Spulen' 0,22uH have slightly different values) I am finished with my
          first two boards now - and they work :-)
          I used Jörg's firmware version from 8/2000 that comes with the download
          of RS232-EEG. I had to do some minor changes to get it working. (there
          was a compile-error at uart.c, maybe only at my version of avr-gcc).
          I have problems with 50-Hz humm (I can reject it to an amount that I
          actually see brainwaves only when i connect myself to GND, can somebody
          help here ?
          I also get this noise when I use battery-power. Could shielding of the
          Electrode-cables help ? I don't fully understand the concept of the
          right-leg-driver - is it ok when i use the average-signal from the
          earlobes ?)

          I ordered two (expensive) bluetooth-modules to test this possibility for
          wireless transmission. (I hope bluetooth becomes more affordable, I use
          it for my prototype because a SPP-module should be easy to apply. It has
          a range of max. 15 m)
          the two ModularEEG-boards now sit in a plexi-box with 4 buttons for
          control-inputs for the software, 1 LED (indicates data transmission), 1
          battery-pack, and I hope soon the bluetooth -module. the box could be
          mounted at the belt or weared on the chest.)

          I wrote my first test-applikation in delphi2, win32. I do not have linux
          installed, but the openEEG-project is yet another reason to do. I hope
          I'll get that in the next month or so. Does someone have some tips on
          whats useful (what distribution, C-Compiler, sound- or open-gl - libs) ?

          I love the openness of the design of Dave's Biosensory-Library and would
          like to contribute where I can. I think about ways for a bio-triggerd
          environment using 3d-graphics and various sounds for some time now - for
          me the things get more realistic yet. Personally, I would like to have a
          proper sound and graphic - output better today than tomorrow, but in our
          case a step-by step development seems to be the best.
          Are there some low-level tools, classes or dll's, that programmers can
          use ?
          A stream-oriented design like Dave points out on his homepage looks good
          to me.


          Best Regards,
          Chris.
        • sleeper75se
          Hi Chris, great work! I think it is really nice that you have built the ModularEEG already! ... Do you mean 22uH? ... Do you mean ModularEEG ground or ground
          Message 4 of 9 , Jul 11, 2002
            Hi Chris,

            great work!

            I think it is really nice that you have built the ModularEEG already!

            > After the downloads (eagle-cad, avr-gcc, SP12), printouts, PCB,
            > orderings (I got most of the parts here in vienna, 1 capacitor 0,3u
            > and 4 'Spulen' 0,22uH have slightly different values) I am finished
            > with my

            Do you mean 22uH?

            > I have problems with 50-Hz humm (I can reject it to an amount that I
            > actually see brainwaves only when i connect myself to GND, can
            > somebody help here ?

            Do you mean ModularEEG ground or ground as in "earth" (eg a
            radiator....)?

            > I also get this noise when I use battery-power. Could shielding of
            the
            > Electrode-cables help ?

            What kind of noise is it? Could you describe it more in detail?

            Try connecting a large (>100uF), low-impedance capacitor across the
            battery (to lower its impedance) and see if that helps. Does anyone
            else on the list have any suggestions? Joerg, Jim-M?

            > I don't fully understand the concept of the right-leg-driver -
            > is it ok when i use the average-signal from the earlobes ?)

            Actually, the DRL is an output and replaces the regular passive
            ground lead. It is part of a regulator circuit that tries to suppress
            low-frequency common mode signals such as 50Hz hum about 100 times.

            The DRL should work anywhere (as far as I know). Try putting it
            farther away from the head (on the arm for example) and see if there
            is a difference in how well (or poorly) it works.

            Hum caused by electrode-impedance mismatch will remain unaffected,
            and may only be reduced by more careful cleaning and abrasion of the
            scalp. However, if the hum does not saturate the amplifiers at any
            time, you can filter the signals digitally with a 50Hz notch filter.
            I can get you some source code for you to try, if you like.

            Another thing you can try, to reduce the noise:

            Put the amplifier board in a metal box and connect the box to virtual
            ground with a short wire, near the amplifier inputs. Drill holes just
            large enough for the electrode wires and ribbon cable to pass through.

            Ok, to sum it up, the things you can try are:

            * Place a large low-impedance capacitor (>100uF) at the battery.
            * Place DRL electrode farther away from the head
            * Put the amplifier in a metal box (and shield the electrode wires)
            * Add a digital 50Hz notch filter.
            * Clean the scalp more carefully.

            Please let us know what you do, and what results you get, we'd really
            appreciate it!

            Btw, consider signing up to the new list at
            http://lists.sourceforge.net/lists/listinfo/openeeg-list so that we
            can continue the discussion over there... :o)

            Regards,

            Andreas
          • Chris
            ... yes ;ö) ... I mean GND1 (from the power supply). I also tried analog-ground, that didn t affect the scene much. ... a 50-hz - signal, ranging the full
            Message 5 of 9 , Jul 11, 2002
              sleeper75se wrote:

              > > After the downloads (eagle-cad, avr-gcc, SP12), printouts, PCB,
              > > orderings (I got most of the parts here in vienna, 1 capacitor 0,3u
              > > and 4 'Spulen' 0,22uH have slightly different values) I am finished
              > > with my
              >
              > Do you mean 22uH?
              >

              yes ;ö)

              > > I have problems with 50-Hz humm (I can reject it to an amount that I
              > > actually see brainwaves only when i connect myself to GND, can
              > > somebody help here ?
              >
              > Do you mean ModularEEG ground or ground as in "earth" (eg a
              > radiator....)?
              >

              I mean GND1 (from the power supply). I also tried analog-ground, that didn't
              affect the scene much.

              > > I also get this noise when I use battery-power. Could shielding of
              > the
              > > Electrode-cables help ?
              >
              > What kind of noise is it? Could you describe it more in detail?
              >

              a 50-hz - signal, ranging the full scale of the inputs (0 - 1024). even when
              i try to measure stronger signals like EKG, i don't see anything unless i
              touch GND1.I searched the archives of schematics once more and found the
              'new-design-folder' of Jörg's rs232eeg, which shows a shield driver for the
              electrode cables, which isn't implemented in the modular-EEG- designs. Why
              isn't that one used - could it guide the signals ?

              > Try connecting a large (>100uF), low-impedance capacitor across the
              > battery (to lower its impedance) and see if that helps. Does anyone
              > else on the list have any suggestions? Joerg, Jim-M?
              >

              I can try that. makes this also sense when i use a net-adaptor ? in
              modularEEG v02-digital schematics I found the hint that the DCDC-converter
              shouldn't be usedwhen driving in battery-mode. there is also another 7805S in
              the voltage-section.
              Is this necessary for battery-mode ? when i just replace the net-adaptor with
              a battery, the signal looks pretty much the same to me...

              > > I don't fully understand the concept of the right-leg-driver -
              > > is it ok when i use the average-signal from the earlobes ?)
              >
              > Actually, the DRL is an output and replaces the regular passive
              > ground lead. It is part of a regulator circuit that tries to suppress
              > low-frequency common mode signals such as 50Hz hum about 100 times.
              >
              > The DRL should work anywhere (as far as I know). Try putting it
              > farther away from the head (on the arm for example) and see if there
              > is a difference in how well (or poorly) it works.
              >
              > Hum caused by electrode-impedance mismatch will remain unaffected,
              > and may only be reduced by more careful cleaning and abrasion of the
              > scalp.

              ok, it couldn't do all the work. maybe my DLR doesn't work at all ?for
              cleaning and mounting I currently use a granular-like, non-abrasive
              electrode-gel, watered bridge-electrodes and a grid-like plastik
              electrode-cap. that fits the needs, but I'm not sure concerning the electrode
              cables/shielding. I currently make a 1-cablestrng-connection from the cap to
              the beld, where the EEGamp is weared.

              > However, if the hum does not saturate the amplifiers at any
              > time, you can filter the signals digitally with a 50Hz notch filter.
              > I can get you some source code for you to try, if you like.
              >

              does this mean to zero the 50Hz-bin in the fft and retransform to time-scale
              ? could such signal processing be done 'on-the-run' at the avr ?I'm heaviliy
              interested in fft-resources (my fft has neither windowing, nor any signal
              analysis like coherence yet ...)

              > Another thing you can try, to reduce the noise:
              >
              > Put the amplifier board in a metal box and connect the box to virtual
              > ground with a short wire, near the amplifier inputs. Drill holes just
              > large enough for the electrode wires and ribbon cable to pass through.
              >

              I tried this already, I senses plausible to me. Unfortunately the shielded
              box didn't give a better result in my case.

              > Please let us know what you do, and what results you get, we'd really
              > appreciate it!
              >
              > Btw, consider signing up to the new list at
              > http://lists.sourceforge.net/lists/listinfo/openeeg-list so that we
              > can continue the discussion over there... :o)
              >

              ok!

              > Regards,
              >
              > Andreas
              >

              thank you for your fast reply and the information.

              Best Regards,
              Chris.
            • Michal Wallace
              ... This is going to turn into a mess. If we re serious about moving, either: a) make the sf list a subscriber to the yahoo list and vice versa so both lists
              Message 6 of 9 , Jul 12, 2002
                On Thu, 11 Jul 2002, sleeper75se wrote:

                > Btw, consider signing up to the new list at
                > http://lists.sourceforge.net/lists/listinfo/openeeg-list so that we
                > can continue the discussion over there... :o)

                This is going to turn into a mess. If we're serious about
                moving, either:

                a) make the sf list a subscriber to the yahoo list and vice
                versa so both lists get the same content.. [I'm pretty
                sure yahoo can back up a sf list anyway - the old egroups
                could]

                or:

                b) shut off the ability to post to the yahoo group and put a
                note up saying to move to sf.


                And yeah, someone should download the yahoo group because
                if it's not active for 6 months or so, yahoo deletes it
                (after giving the owner a chance to keep it alive)

                There's an old egroup-archiver here:

                http://www.marmoset.net/~knail1/scripts/ea/ea.html

                Cheers,

                - Michal http://www.sabren.net/ sabren@...
                ------------------------------------------------------------
                Switch to Cornerhost! http://www.cornerhost.com/
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              • Jim Peters
                ... I think we need to do something closer to (b). Actually, the new list has *already* picked up a new person who is interested in contributing to the
                Message 7 of 9 , Jul 12, 2002
                  Michal Wallace wrote:
                  > This is going to turn into a mess. If we're serious about
                  > moving, either:
                  >
                  > a) make the sf list a subscriber to the yahoo list and vice
                  > versa so both lists get the same content.. [I'm pretty
                  > sure yahoo can back up a sf list anyway - the old egroups
                  > could]
                  >
                  > or:
                  >
                  > b) shut off the ability to post to the yahoo group and put a
                  > note up saying to move to sf.

                  I think we need to do something closer to (b). Actually, the new list
                  has *already* picked up a new person who is interested in contributing
                  to the software side.


                  > And yeah, someone should download the yahoo group because
                  > if it's not active for 6 months or so, yahoo deletes it
                  > (after giving the owner a chance to keep it alive)
                  >
                  > There's an old egroup-archiver here:
                  >
                  > http://www.marmoset.net/~knail1/scripts/ea/ea.html

                  I could try using this (and if it doesn't work, I know enough Perl to
                  fix it), but it requires that the group is viewable for non-members
                  (probably to save messing with cookies).

                  If I'm going to be the one who grabs the archive, can someone turn off
                  member-only viewing, and let me know ? Then I'll give it a go.

                  Jim

                  --
                  Jim Peters (_)/=\~/_(_) jim@...
                  (_) /=\ ~/_ (_)
                  Uazú (_) /=\ ~/_ (_) http://
                  B'ham, UK (_) ____ /=\ ____ ~/_ ____ (_) uazu.net
                • sleeper75se
                  Hi all, I ve mailed the list owner (Yaniv) about your suggestions (readonly, public archive, moving-notice). I will let you know when things are ready.
                  Message 8 of 9 , Jul 13, 2002
                    Hi all,

                    I've mailed the list owner (Yaniv) about your suggestions (readonly,
                    public archive, moving-notice). I will let you know when things are
                    ready.

                    Regards,
                    Andreas

                    Sign up to the new list here:
                    http://lists.sourceforge.net/lists/listinfo/openeeg-list
                  • Jim Peters
                    ... Perhaps the Yahoo list could be a subscriber to the SF list, so that people who just want to keep monitoring the situation don t have to change anything,
                    Message 9 of 9 , Jul 13, 2002
                      Michal Wallace wrote:
                      > This is going to turn into a mess. If we're serious about
                      > moving, either:
                      >
                      > a) make the sf list a subscriber to the yahoo list and vice
                      > versa so both lists get the same content.. [I'm pretty
                      > sure yahoo can back up a sf list anyway - the old egroups
                      > could]

                      Perhaps the Yahoo list could be a subscriber to the SF list, so that
                      people who just want to keep monitoring the situation don't have to
                      change anything, but we could somehow stop postings being permitted on
                      the Yahoo list. Is that do-able? I've never managed a Yahoo list.

                      Surely, with your solution, even if the mail-loops of two lists
                      subscribed to one another don't get us, the double subject-headers
                      will ([buildcheapeeg] vs [openeeg-list]).

                      If we can make the Yahoo list a read-only copy of the SF list, and
                      move all active discussion over there, that might well be the best
                      solution.

                      Really, the whole point was to simplify things, not make them ever
                      more complex and intertwined.

                      Someone else has popped up on the SF list now -- it is certainly
                      getting attention.

                      http://lists.sourceforge.net/lists/listinfo/openeeg-list

                      Let's sort this out folks!

                      Jim

                      --
                      Jim Peters (_)/=\~/_(_) jim@...
                      (_) /=\ ~/_ (_)
                      Uazú (_) /=\ ~/_ (_) http://
                      B'ham, UK (_) ____ /=\ ____ ~/_ ____ (_) uazu.net
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