chipaudette
chipaudette
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Hi Yen, I wasn't aware of this point that you made... >> If I remember correctly from the OpenBCI website it mentioned never connect the Analog pin back to GND or it might damage the board. If it weren't for this, I would have said t…
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Continuing the discussion of the wireless link, I think that it is important to remember that any hard-wired link (SPI, I2C, UART, USB) have a safety risk to the user. You do not want to be hardwired to anything that is then plugged into a wall pow…
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I looked into python-mne...that's cool! I hadn't seen it before. It definitely looks to me like a post-processing tool, hence it's ability to do zero-phase filtering. They give the option of two types of zero-phase filtering, IIR or FFT... h…
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What are you trying to do that is so sensitive to phase distortion? Doing a bessel or butterworth IIR high-pass filter will have phase distortion (ie, different frequency components will pass through with different latencies) but that's not really …
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To be clear, the EEG sample rate limit has nothing to do with 8-bit vs 32-bit...the limit on the EEG sample rate is due to the RFDuino wireless unit on the board. The RFDuino wireless unit can only go so fast, so if you want 8 channels of EEG, your…
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There's no doubt that 32-bit platforms are more capable. But, the reason for getting an 8-bit board is Arduino compatibility. When it comes to programming the board, the 8-bit OpenBCI board *is* an Arduino Uno, no "ifs" or "buts". Load the Arduin…
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Hi Kevin, As discussed in the posts preceding yours (ie, prior to William merging your post with this thread), the big DC offset is normal in the data. The Processing GUI applies a bandpass filter to the data prior to plotting it. This filter re…
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Regarding the bias pins and your home-made adapter... On the 16-chan OpenBCI unit, all four bias pins should be producing the same signal. So, for the bias, there's no home-made adapter necessary. But, for the SRB pins, the SRB pins on the da…
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Joel and Conor and I extended this hack. Now, five people can join together to brain-control toys...this time we used a swimming shark balloon instead of the little spider robots. I think that the swimming shark is pretty cool. If you're i…
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Measuring the resistance of this stuff is not as easy as it appears on first glance. It often has a sizeable surface resistance that complicates the measurement of its volume resistance. So, one should really do a 4-wire resistance measurement vs …
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Hey jfrey, Regarding... >>> I feel a bit stupid; I've soldered the daisy module and now a pin (the AGND) is getting in the way of the battery pack's cable lead and it's very difficult to plug / unplug it from the board. Even if my so…
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Hi, For a complicated project like yours, I would suggest that you NOT do the alpha detection on the Arduino/chipKIT processor that is on the OpenBCI board itself. I would recommend that you do the alpha detection on the PC, in the Processing GUI…
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Hi Jaimze, I've used OpenBCI to record EKG (or "ECG", depending on whether you like the German or the Latin): http://eeghacker.blogspot.com/search/label/ECG As Omphalosskeptic suggested, BrainBay can be a good choice. But, if you really …
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Hi, Those two questions are squarely in my lap, as I wrote those parts of the Processing GUI. "No BP": The "no BP" filtering means "No Bandpass", which means that there is no bandpass filtering being applied. When there is a bandpass filter …
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Following up on the B1 eurorack device mentioned by @shivasongster, they now have a desktop unit. http://neurogadget.com/2015/02/02/bi1brainterface-soundmachines-first-commercially-available-brainwaves-synthesizer-interface/10758 Chip
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You can also re-reference the data after the fact... If you used an earlobe for reference during recording, and if you instead want Cz as a reference, you simply subtract the signal recorded from Cz from the signal recorded from the other electrod…
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I've done all of my programming using the Arduino IDE for the 8-bit board and the MPIDE (which is Arduino-like) for the 32-bit board.
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Hello Mohit, For the Mu wave work that I described at: http://eeghacker.blogspot.com/2013/11/waveforms-from-homemade-electrodes.html It looks like I did C3 vs Cz as you said. It looks like I did not use any bias connection at all. If I …
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I think that you might be misinterpreting my figures....the Mu waves only appear when I'm relaxed and they disappear when I move my hands. I think that this confirms your expectation.
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I did some trials back with the pre-Kickstarter OpenBCI hardware. I'm pretty sure that I saw Mu waves, but I'm no expert in this area. Unlike eyes-closed Alpha, it was indeed challenging to see the Mu waves. Here are some posts describing what I…
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You are certainly correct that your output doesn't look right. As a debugging technique, I would create fake data to send through your filters. I would create a simple data vector that holds a sine wave at a given frequency, say 10 Hz. Pass it t…
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This showed up on the OpenBCI Twitter feed...new style of dry electrodes for ECG/EMG...maybe could be repurposed into EEG... https://www.medgadget.com/2015/01/new-dry-electrodes-allow-long-term-ecgemg-monitoring-even-while-in-motion.html ...I…
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That's pretty sweet! The use of multiple speakers for the multiple EEG channels is a good idea. How did you get multiple audio streams for the differetn speakers? Did you have a multi-channel sound card for your computer? Chip
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Note that the GUI "playback" mode only happens on the PC...the OpenBCI hardware is not involved in any way. So, if you're looking to prototype your new OpenBCI code (as it runs on the hardware), the playback isn't going to help. You can, however,…
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It's also important to note that all of the filters in Processing assume that the OpenBCI sample rate is 250 Hz. If you run at a different sample rate, these hard-coded filter coefficients are all going to be wrong. I wish that there was a Proces…
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I wrote the filters that are in the Processing GUI. As William suggested, I computed the filter coefficients in Matlab. You can see the Matlab command that I used in the Processing source code...specifically the file "EEG_Processing.pde": https:…
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I just bought a set...a get their package deal with the matching lead wires... http://fri-fl-shop.com/product/package-of-25-disposablereusable-dry-electrodes-3-lead-wires-fri-2140-1/ I still would love to find some active electrodes...dry or …
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Unrelated to this forum topic, I've had communications with the guy from Florida Research Instruments...he's a very nice guy...he's really looking to help people out. I think that I might buy a few of these to play with them. Chip
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I'd forgotten about this. Sorry! I took a first look at your data and I confirmed that something is definitely weird about your even numbered channels. To see the data, you can view an HTML version of my IPython Notebook: http://nbviewer.ipython…
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Hi Everyone, I think that I found that old code that ran on the OpenBCI V2 board. I pushed it to my GitHub here: https://github.com/chipaudette/EEGHacker/tree/master/Arduino/OBCI_V2_AlphaDetector Note that it took quite a bit of tuning o…