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Author: katie356

Noise from Electricity – Part 2

See Noise from Electricity – Part 1

KOB (see Gallery-KOB) noticed that the automatic gain control (ACG) doesn’t work as well in Europe. As pointed out in Noise from Electricity – Part 1 the ACG reduces any peaks caused by the electricity in the walls (60 Hz  in the USA and a few other countries and 50 Hz in the rest of the world). KOB lives in Europe and if you look at his readings they do tend to have small peaks at around 50 Hz, for example “KOB eyes closed”, 5th second:  

Luckily these peaks are small enough that they shouldn’t have much of an effect on the overall results. My understanding is that the Mindwave was developed in the U.S.A., and it could very well be that its ACG is more sensitive to the American 60 Hz, and less sensitive to the European 50 Hz.

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Noise from Electricity – Part 1

See Noise from Electricity – Part 2

Curious, I ran a test where I took off the Mindwave headset and saved the results. The Brainwave Analyzer showed a large amount of Gamma “brainwaves”. Surprised, I googled around and it turns out that EEG readers are so sensitive that they pick up the electromagnetic waves from the alternating current (AC) flowing within the walls.

No Headset I ran a test where I took off the Mindwave, and saved the results:
No-Headset-01No-Headset-02
Headset Slipped? KOB (adult male) baseline1-relaxing with eyes open
Mindwave512-KOB-baseline1-relaxing with eyes open-MedianMindwave512-KOB-baseline1-relaxing with eyes open-Bands

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How to Calculate Frequencies and Amplitudes

This is what a one second sample of brainwaves looks like when graphed:one-second-graph

So based on these squiggly brainwaves, how do we calculate frequencies and amplitudes?

Luckily mathematicians have come up with a solution called “Spectrum Analysis using Fourier transform”. The basic idea is that every wave, no matter how complex and irregular, can be represented by combining a number of simple (sine and cosine) waves.

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EEG and 5 Activities

5 new samples for 5 activities:

Not surprisingly my test subject’s brainwaves were most engaged while playing guitar and must less engaged while watching a video. What did surprise me was how little his brainwaves were engaged while playing 3-D Pong. (Click on the graphs to enlarge.)

If you have access to an EEG reader, please let me know if you have similar or different results!

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The Brainwave Analyzer

Announcing the brand new Brainwave Analyzer ! !

For instructions see: Brainwave Analyzer Help

Written by the brilliant Nayuki (of the Nayuki Project)

Note, the Brainwave Analyzer is a free, open source program (optimized for Chrome).

OpenVibe-Drawing                OpenVibe-Drawing-per Minute

Brainwaves while drawing                                                Median power per minute

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OpenVibe – Part 3

Note, see OpenVibe – Part 1 and OpenVibe – Part 2

Now a walk-through (Part 3 of 3) of using your Mindwave and OpenVibe to save a sample of your brainwaves to a file.

Start “openvibe designer”, then open your acquisition-signal-display.xml” and your acquisition-file-csv.xml”

Capture1

Start Neurosky’s “Thinkgear Connector”, and make sure the “Starting port” is correct.

Capture4

Start “openvibe acquisition server”, and choose a driver “Neurosky Mindset”

Capture2

Click on “Driver Properties”, and make sure the “COM Port” is correct” and you’ll want a “Sampling frequency” of 512.

Capture3

Click on “Connect”, then once it is connected, click on “Play”.

Capture4

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OpenVibe – Part 2

Note, here is  OpenVibe – Part 1

This next part is about creating two boxes (processing algorithms), one to view your live brainwaves, and one to save the brainwave readings to a file (to be used for later analysis).

Box 1 – Signal Display

The first step is to start the OpenVibe Designer, and open the “generic-stream-reader.xml” (if you are not sure how, see OpenVibe – Part 1).

Create an OpenVibe folder C:OpenVibe

Next Save the “generic-stream-reader.xml” as “acquisition-signal-display.xml” in the C:OpenVibe folder.

OpenVibe11

On the right-hand side of the OpenVibe Designer are the components of the processing algorithms.

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