visualisation: alpha and absence of alpha waves

This is what the plotting of data for alpha waves looked like in version 1 of the Max/MSP interface for the Staalhemel project.

data plotting for a running average of alpha waves

In the event windows on the left you see 3 windows with graphs colored (mainly) in red. The top window doesn’t show much information here; peaks will appear if there is synchronization in maximum values for alpha waves between both hemispheres. The middle window shows peaks of alpha waves over time. Color switches between red and black for each new visitor. The bottom graph reports the absence of alpha waves, which functions as an indicator of beta waves. The first version of the IMEC software did not deliver beta waves, but indicated if there was an absolute absence of alpha. This allowed me to infer moments of concentration (and the appearance of beta waves).

On the ‘frequency’ matrix display in the main window you see which steel segments are activated. This matrix represents the whole Staalhemel installation with a video window of 6 by 12 pixels (segments): the darker pixels indicate longer intervals between impacts for a particular plate. If they are white they are hammering at maximum speed (interval of 40 ms) and if they’re black they are off. The screenshot here shows a moment of concentration and the immediate response in activation of steel segments. You can see that just before this moment there was a sustained period of concentration, only interrupted by rather small amounts of alpha waves. This happened when I was working on the software while wearing the EEG headset and it tells how I was (minimally) distracted 4 times in that thinking process.

At STRP Festival in Eindhoven this version was installed for the last time.
The first day of the festival I did a testrun of the new software, Staalhemel version 2. In this update alpha and beta wave information for 8 channels is visualised. Due to certain limits and interferences this 8-channel version is not fully operational yet. This version maps the layout of your head to the installation matrix: front panel rows represent left and right frontal area of your brain, next rows show results from the side electrodes and top and back of the head are translated to the last rows of steel plates.

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