wjcroft
wjcroft
William J. Croft, Lightfield Systems, Mount Shasta, CA, USA. My website on neurofeedback, biofeedback: http://lightfield.com/nf.htm
LinkedIn profile: http://www.linkedin.com/in/wjcroft/
About
- Username
- wjcroft
- Location
- Mount Shasta, CA
- Joined
- Visits
- 20,583
- Last Active
- Roles
- Member, Administrator, Moderator
- Website
- https://lightfield.com/nf.htm
- @wjcroft
- Location
- Mount Shasta, CA
- Interests
- William J. Croft; heart-intelligence, peak performance, creativity, collaboration, mentoring, transformative technologies
- wjcroft
Comments
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Hi Gaia, Have you tried emailing with Customer Support (contact at openbci.com) to discuss possible options? Such as other electrode caps, gel versus gel-free, etc.? The Ultracortex is designed as a dry system and cannot be easily converted to we…
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Here is a 10-10 layout for EasyCap, XYZ coordinates: https://web.archive.org/web/20150401012558/http://www.easycap.de/easycap/e/downloads/M1_XYZ.txt From: https://web.archive.org/web/20150331182813/http://www.easycap.de/easycap/e/downloads/…
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Hi Zenton, Have you tried a search for other sfp files? Any 10-20 or 10-10 layouts should do. OpenBCI Ultracortex only chose the layout you mention because of the 16 channel limitation. https://www.google.com/search?q=sfp+electrode+location+fi…
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Hi Wmm, Each Ganglion radio packet contains TWO sample values. This is why the Sample Index repeats once for each sample pair. Timestamps are assigned NOT at the Ganglion board, but when the radio packets travel through the USB or Bluetooth OS…
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Paul, hi. The dry electrodes used in the kit are very sensitive to the amount of pressure applied on the skin by the band. Have you tried tightening the band somewhat? You don't want to make it uncomfortable to wear. If you look at the tips of…
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I'm glad you are seeing an improvement. But your signal levels are STILL out of line of what to expect with EEG. Normal EEG is below 100 uV. From the red trace above, I see you have a slow drift upwards. This seems to imply that your filtering still…
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AC is ALWAYS used to measure EEG impedance. Have said this multiple time now. All that matters is the RELATIVE voltage differential. Not absolute voltages. What is your goal with Ganglion, have you been able to use it successfully?
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You can download it here: https://www.researchgate.net/publication/7942803_Tallgren_P_Vanhatalo_S_Kaila_K_Voipio_JEvaluation_of_commercially_available_electrodes_and_gels_for_recording_of_slow_EEG_potentials_Clin_Neurophysiol_116799-806
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No, no DC offset. DMM will not work for EEG impedance. There are special meters for practitioners with older amps. https://www.google.com/search?q=eeg+impedance+meter Actual AC must be used to avoid the polarization aspect. A DC offset would p…
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I have not looked at your code. Have you just tried running one of the example Python files on the Brainflow doc site? I would do that first because it avoids any dependencies such as MNE. https://brainflow.readthedocs.io/en/stable/Examples.html#…
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If you examine the multiple sheet schematic, https://github.com/OpenBCI/Ganglion_Hardware_Design_Files/blob/master/Ganglion_SCH.pdf On sheet 2 is shown an output "micro-amp sense" line. All that is needed to use ohm's law, E = IR, or R = E/I,…
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Hi Verve, Here is some background on how current injection can be used to measure impedance, on the ADS1299 (Cyton) chip. https://eeghacker.blogspot.com/2014/04/openbci-measuring-electrode-impedance.html https://eeghacker.blogspot.com/2014/04…
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There are TWO types of impedance measurements of importance with EEG. The primary one is the SKIN IMPEDANCE, which reflects the quality of the connection between the electrode / paste / gel / and skin. The GUI can show you that figure in the impedan…
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Hi Zoto, I'm not sure what you are referring to as 'clips to ground'. Are you referring to the ear clip type of electrodes? What are the scalp electrodes you are using? Is this a dry electrode or wet/gel/paste electrode situation? https://docs…
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Richard @retiutut, the person posting above on April 21 is 'Cindy' in Taiwan, who claimed to have bricked their board after removing the mainboard RFduino and attempting some type of 'wired usb' interface. There is a Zendesk trail [Ticket 35359] for…
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Mods to the board or firmware are generally NOT recommended. The very old threads you refer to, regarding Serial1 and Serial0 'wired connection' are from an unsupported, user initiated, one-off 'hack', from around 2016, 2017, (almost 10 YEARS ago). …
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@SimpleRain said: ... so I wonder how do you convert from -80000 to .5Hz. I am doing my work on Jupyter notebook so I might not be able to use tools in apps like LSL. https://www.google.com/search?q=example+of+applying+bandpass+filter+in+…
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Please email [email protected]
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@SimpleRain, did you read my previous comment and link? You just apply a bandpass or highpass filter, such the DC offset, below .5 Hz disappears.
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Cindy, have you tried reloading the factory, default, normal firmware? Before proceeding further, I suggest you email as instructed below. https://docs.openbci.com/Cyton/CytonProgram/ ## caution Note, you do not need to do any board prog…
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Hi Lee, Here is the reply from our engineering staff: Just looked at original drawing. We specified COVESTRO MAKROLON 2405 AKA: Polycarbonate Here’s what I found online for material properties https://solutions.covestro.com/en/p…
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Here is a new release of the 'SLEEPYLAND' automated sleep staging platform: https://www.linkedin.com/posts/lfiorillo_sleepyland-sleepresearch-sleepstaging-activity-7318898804420706305-Wo9L/ https://github.com/biomedical-signal-processing/sleep…
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All Brainflow devices return data streams in microvolts. No conversion needed.
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Hi JC, Let's see if @Andrey1994, the Brainflow founder/developer has any suggestions. If that does not work, I would suggest rather than searching for the 'past solution', just to create a new topic. Regards, William
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Hi Huchenbo, Are you sure you are using Wifi Shield? Those systems have not been sold for some years. The normal Cyton radio link is via a form of Bluetooth, not Wifi. The raw data is always in microvolts, no multiplying by scale factor. Bewar…
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Hi Etc, Nice going with your Neurofly tests. re: P300 spellers Those spellers based on P300 are sometimes hard to train or configure for your subject. There is another type of BCI paradigm based on VEP Visual Evoked Potentials. Here are two…
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The noise source primary frequency seems to be about 7 Hz, as seen from the time series and FFT. Then harmonics of that primary at higher frequencies (lower amplitude than primary.) Wide price range on the physical hardware meters: https://www…
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I already replied to you on the other thread, where you enquired about reflashing the Cyton. DON'T. Another point to make is that when electrodes / pins are free floating and not connected to anything, they act like radio antennas. Again underlining…
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... ... if the tests are marginal with the think pulse electrode, adding some water to the electrodes will help, right? Doubt you will need this, because the developer of the Thinkpulse active electrodes is not using any additional water…
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The Time Series and FFT graphs you show, are evidence of 'environmental noise' in your area. Such as from LED lighting, power supplies, wireless gear / cell towers, AC power line sources such as extension cords, conduits, etc. Have you tried moving …