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EOG sensors & software

December 12, 2013, 5:57 am
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Hi, I'm new to OpenBCI...first post.

Has any one done any measurement of noise and signal quality with dry (active) electrodes? I noticed that all of the videos showing OpenBCI always see use wet electrodes. I'm looking to develop an ambulatory sleep monitoring solution that uses dry electrodes...wet electrodes just aren't practical for home use on an ongoing basis.

I seem to recall a list of signals that could be collected with this solution. I saw lots of different signals listed (somewhere...maybe on TI 1299 Data sheet) but EOG was explicitly not mentioned. Can you get EOG readings with this solution?


Regards,
Jet
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High CPU usage

February 9, 2017, 8:52 am
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Hi,

I'm experiencing very high CPU usage with the OpenBCI GUI v2 (and also with the custom software that I developed in Processing to interface with the OpenBCI): the %CPU reaches on average 100%, with peaks well above it (see attached figure). 

I'm mainly using the OpenBCI 32 - bit board with custom v2 firmware (the only difference with the default firmware is the analog reading from an analog PIN), and I'm using Processing 3.2.1 on a Mac with OS El Capitan 10.11.6. I also tried it with the Ganglion Board (the screenshot refers to that trial) and the results are the same. 

Has anybody ever experienced something similar? 

Thanks

image

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Board disconnecting all the time...

March 15, 2018, 3:11 pm
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Hi,

I just bought a ganglion board, for artistic purpose.

I just tested it yesterday, and i have a big issue. The board work, i have data in the GUY, and the board connects with BLE propely. But each time, after 30sec-5mn, the board disconnects from itself, the led starts blinking, and i have to restart the software each time...

I tried many things, such as moving the board just next to the bluetooth receiver, or this kind of stuff... I wanted maybe to update the board, but the version seems okay : ( Firmware Revision String 1.1.0 and Software revision string 1.1.2)

Other thing that is strange too, when i configure the data source in the GUI, I have to select "BDF+" instead of "OpenBCI" because if i do so, it will freeze when i click "START SYSTEM"...

I'm a little bit lost, and this problem is really ennoying. I hope that it is a knowned issue for you, and that you have the solution...

Sincerely yours,

J-d
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BIAS. Why do I need it?

March 16, 2018, 2:58 am
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I'm trying to understand the need for the BIAS electrode when taking EEG measurements. 

If I’m not
mistaken, in the default operation mode the ADS1299 amplifies the voltage
difference between any channel and the SRB2 pin, digitalizes it and sends it
over to the computer. My question is: If this
process only takes into account the voltage difference between two electrodes,
why is it so important to have an additional electrode connected to the BIAS
pin?


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Lost data using LSL and Matlab?

February 26, 2018, 11:43 am
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Hello,

I want to stream raw data from my Ganglion board to Matlab using LSL. I successfully run the python code to stream data via LSL and I pull this data using the library in Matlab. However, there seems to be some kind of data loss or an inconsistent sampling rate (see pictures). I created a 10Hz sine wave using a waveform generator. First picture is what I get using LSL and Matlab. Second picture is data recorded using OpenBCI GUI. Any ideas on what could be happening? Thanks!!

LSL + Matlab:

image



Recording in OpenBCI GUI:

image
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BLE dongle does not show up under as COM port?

February 10, 2018, 6:32 pm
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"Failure: Communications timeout - Device failed to poll host"

February 9, 2018, 8:54 pm
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Hi guys!
I got the Mark IV and Cyton but its not working. When I click status in the Radio Configuration it says Failure: Communications timeout - Device failed to poll host. When I click Autoscan the blue and red lights blink and then it says the same thing. I also have a Ganglion board and it works perfectly in the same headset.
Any help would be greatly appreciated, thank you
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Sample rate of 1kHz for EMG cursor control, How?

February 22, 2018, 8:34 pm
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I'm trying to build a facial EMG device to control a cursor. The frequency range of EMG is between 20 and 500Hz. I would need to sample at 1kHz but I only need one channel. It seems that the limitations of the RF and Bluetooth don't allow real time with >250Hz. If I use only one channel, is it possible to increase the sample rate to 1kHz without loosing samples in real time? 

I can't use the WiFi shield due to wifi limiations. 
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All channels railed

February 24, 2018, 10:18 am
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Hello!

I bought a cyton, and whenever I connect it to electrodes, or even run my fingers over the pins, they usually show RAILED on the GUI. 

How do I fix this? It's really bothering me and preventing me from interacting with the tech. 

Thanks!
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OpenBCI_GUI 3.2.0 and Max 7: Networking

February 27, 2018, 12:23 pm
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Hello All,

The current GUI for Mac is working well via OSC messages, and I'm doing my best to create a template to make the data usable with Max 7 objects. I have a few questions to make this possible. The data looks correct when displayed on multislider objects, but I don't understand how the received OSC values correlate to what I see in the GUI in regards to measurements.

How do I convert the Time Series amplitude to microvolts?
Recorded Data Range on Synthetic Channel 1: -150. to 150. (floating point)

I believe I can plot the data logarithmically as in the GUI in Max, but it doesn't seem to match what the GUI shows with synthetic data. How do I interpret Band Power to (uV)^2 / Hz per channel?
Recorded Data Range on Synthetic: 0. to 5. (floating point)

Can I use the data from the previous question to create a focus algorithm in Max per the description in the GUI?
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Networking with LSL makes GUI crash, why?

March 16, 2018, 7:47 am
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Hello guys!

I have a problem to run OpenBCI_GUI. When I select to send packages through LSL, the GUI freezes and the following trace is shown:

...
LSL selected from Protocol Menu
openBCI_GUI: startButton was pressed...starting data transfer...
startRunning...
DEBUG: start data transfer
port not open
Stream update numChan to 8
nPointsPerUpdate 10
dataToSend len: 80
[TimeSeries, obci_eeg1, EEG, 8, 1]
java.lang.RuntimeException: java.lang.NoClassDefFoundError: com/sun/jna/Platform
at processing.opengl.PSurfaceJOGL$2.run(PSurfaceJOGL.java:412)
at java.lang.Thread.run(Thread.java:748)
Caused by: java.lang.NoClassDefFoundError: com/sun/jna/Platform
at edu.ucsd.sccn.LSL.<clinit>(LSL.java:976)
at edu.ucsd.sccn.LSL$StreamInfo.<init>(LSL.java:123)
at OpenBCI_GUI$Stream.openNetwork(OpenBCI_GUI.java:24826)
at OpenBCI_GUI$Stream.start(OpenBCI_GUI.java:24296)
at OpenBCI_GUI$W_networking.startNetwork(OpenBCI_GUI.java:24122)
at OpenBCI_GUI$W_networking.mouseReleased(OpenBCI_GUI.java:23888)
at OpenBCI_GUI$WidgetManager.mouseReleased(OpenBCI_GUI.java:25604)
at OpenBCI_GUI.mouseReleased(OpenBCI_GUI.java:11854)
at processing.core.PApplet.mouseReleased(PApplet.java:2785)
at processing.core.PApplet.handleMouseEvent(PApplet.java:2694)
at processing.core.PApplet.dequeueEvents(PApplet.java:2607)
at processing.core.PApplet.handleDraw(PApplet.java:2448)
at processing.opengl.PSurfaceJOGL$DrawListener.display(PSurfaceJOGL.java:849)
at jogamp.opengl.GLDrawableHelper.displayImpl(GLDrawableHelper.java:692)
at jogamp.opengl.GLDrawableHelper.display(GLDrawableHelper.java:674)
at jogamp.opengl.GLAutoDrawableBase$2.run(GLAutoDrawableBase.java:443)
at jogamp.opengl.GLDrawableHelper.invokeGLImpl(GLDrawableHelper.java:1293)
at jogamp.opengl.GLDrawableHelper.invokeGL(GLDrawableHelper.java:1147)
at com.jogamp.newt.opengl.GLWindow.display(GLWindow.java:759)
at com.jogamp.opengl.util.AWTAnimatorImpl.display(AWTAnimatorImpl.java:81)
at com.jogamp.opengl.util.AnimatorBase.display(AnimatorBase.java:452)
at com.jogamp.opengl.util.FPSAnimator$MainTask.run(FPSAnimator.java:178)
at java.util.TimerThread.mainLoop(Timer.java:555)
at java.util.TimerThread.run(Timer.java:505)
Caused by: java.lang.ClassNotFoundException: com.sun.jna.Platform
at java.net.URLClassLoader.findClass(URLClassLoader.java:381)
at java.lang.ClassLoader.loadClass(ClassLoader.java:424)
at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:335)
at java.lang.ClassLoader.loadClass(ClassLoader.java:357)
... 24 more

What is the correct sequence to perform the transmission via LSL? "Start Data Stream" -> "Start" LSL or the reverse? (same problem in two configs). I also set the print of the configuration screen:

image

I am on Linux Debian 9.0.

Thank you!
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Can I use more than one MyoWare with an OpenBCI board?

March 16, 2018, 8:38 am
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Daisy+pulse sensor

March 16, 2018, 10:21 am
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Hi everyone,

I am new to OpenBCI and have a pulse sensor, cyton+daisy, and a mkIV headset. 

I am trying to go through the various documents but can't find a guide for dummies which says where the three pins from the pulse sensor (purple/signal, black/ground, and red/5v) would connect to the Daisy.

anyone out there reading this - able to help?

Thanks very much for all your work :)

Duncan
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Best way to read .txt file into matlab?

March 16, 2018, 11:23 pm
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Hi all,

Apologies in advance if this has been covered elsewhere (I'm sure it must have been, but surprisingly I could not see anything in the forum).

What are peoples best way to read the Cyton data (.txt) into matlab?

To date I have been opening data recorded by the Cyton with a csvread command. 
eg: 

eeg_data = csvread('OpenBCI-RAW-2018-02-04_12-48-15.txt', 7, 1);


However this is not reading the data correctly. 
Not only does the resulting egg_data.mat file have zeros introduced into every second row, but about the second half of the recording/.txt file is not read into the eeg_data.mat file.

I have sifted through various matlab forums but have not really found a clear answer to best practice for reading .txt into matlab. 

Can someone just cut and paste a reply here, with the matlab commands they would use to open the .txt file recorded by the Cyton board, into matlab?
I just want a matrix of the raw data. 
That would be so helpful.

Cheers,


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/dev/ttyUSB0 is not instiated with Ganglion over Ubuntu

March 17, 2018, 9:27 am
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I am using Ubuntu64 bit and I am trying to use OpenBCI_C. It appears that the code assume that the gangileon instantiates /dev/ttyUSB0 as if it is hardwire connected.
My Gangileon is connect via bluetooth so the interface is hci0.

How can use these libraries if at all ?   
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GUI Hub installation / EADDRINUSE 127.0.0.1

January 20, 2018, 1:27 am
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Hey .
After installing the openBCI hub , it throws an error stating : OPENBCIHUB FATAL ERROR
LISTEN EADDRINUSE 127.0.0.1:10996
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Printing the Ultracortex Mark III frame with an Ultimaker 2 fails

March 19, 2018, 1:13 am
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Hello,

I am trying to build a Ultracortex Mark III with an
Ultimaker 2 and got so far 2 failed prints for the frame. I used support
and lowered the speed but at one point the nozzle was clogged. While
The mechanical parts, cases and in a second try the back half of the
frame were printed successfully, after the failed first attempt of the
front part I am not allowed to do another try on my universities
3D-printer till I consulted with one of the tutors who doesn't come back
till April. If I could show him (via Mail) working parameters, I may
can start earlier. Does anybody printed the frame successfully with an
Ultimaker 2 and could share the files with me? Or alternatively share
plausible settings with me that would prevent another failed print?

Best regard  
Patrick
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Display EEG data on mobile APP?

May 21, 2017, 7:47 pm
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Hello, all.
I want to create a mobile APP which can display the real-time EEG signal. I am wondering whether EEG data recorded by Ganglion and OpenBCI GUI can be sent to our mobile phone or not. If cannot, what change can we do with the data format to send and receive the EEG data?
Please help me solve this. Thank you in advance!
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Ganglion Hardware Connection to Raspberry Pi (SPI or UART)

November 9, 2017, 12:55 pm
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Hi everyone!

I have been working with the Ganglion for a few months now and I'd like to connect it to my Raspberry Pi. However, I don't want to connect to it over bluetooth, which seems to be how most people are connecting the board to the pi. Instead, I'd like to use either an SPI or UART connection (preferably SPI) to connect the Simblee of the Ganglion to the Raspberry Pi's GPIO pins. The main reason for the hardware connection is to improve the sampling rate of the Ganglion (which is severely limited over bluetooth). I also have some other design ideas that require the hardware connection. 

In trying to do this, I have ran into an interesting snag. I was able to connect the Ganglion to my PC over UART via an FTDI cable and view serial output from the Ganglion on the PC (including raw voltage data). However, when I tried to connect the same pins (RX and TX) to the corresponding pins on the Raspberry Pi, something really strange happens. I'm not sure what is happening internally, but the Ganglion seems to fail to output data over the UART connection. Moreover, the blue light on the board starts flashing faintly when its connected to the Pi, even before I turn the Ganglion on. When I do turn the Ganglion on, the blue light starts out blinking, but, after a few seconds, the light stays on solid without any blinking. This strange light show does not occur when I connect the Ganglion to my PC computer via UART through an FTDI cable. 

My only guess is that output voltage of the GPIO pins on the Raspberry Pi is too high to be compatible with the Ganglion, which is overloading the Ganglion. However, this conclusion really doesn't make any sense, as the Raspberry Pi's GPIO pins output 3.3 volts and the Simblee operates at 3.3 volts. Likewise, my FTDI cable is 3.3 volts and the Ganglion works fine with it and my computer. 

Any thoughts as to why this might be happening? 

Please note that I currently have my Raspberry Pi powered via a wall outlet, but I am not allowing anyone to wear the electrodes while it is being powered in this way. Once I get the connection working, I will get a battery pack for my Pi so it can be used to collect voltage data. If there are any other details that I have left out that might be helpful, please let me know. 

Thanks!
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Error with OpenBCI_GUI; Focus_Widget. Cannot connect to COM Port.

March 20, 2018, 8:02 pm
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I have been recently working with the OpenBCI_GUI processing source code to try and achieve sending data/ values to external hardware via serial/COM port in a windows 10 environment. The networking widget of the GUI works fine and appears to be able to establish a link with an arduino I have connected to the same computer. An issue arises however when I try to link the output value from the Focus widget to the same COM port. I continuously receive "serial not present, search 'serial_output' in OpenBCI.pde and check serial settings." I changed the serial_output to my desired COM port first thing and that appears to a have achieved very little. 

Any advice on fixing this?

imageimageimageimage
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