Barak ebay-ed two additional Mindflex headsets, and we tore down three of our four. Our plan was to create a new headset around a pair of noise-cancelling headphones for proper binaural beat entrainment. This meant we had to replace all of the leads on the Neurosky chip with longer silicon wires. This also meant we needed professional help, because the chips were tinier than our soldering skills were questionable.
Luckily, my father is an electrical engineer, so I flew our Neurosky chips home with me over Thanksgiving break and put him to work:
When I returned to NY, our chips were ready to go (with shiny new copper tape electrodes):
Barak came back with cheap headphones, the speakers from which we would install in the shooting range earmuffs we bought off Amazon.
For ICM playtesting that week, I created p5 sketches that—gradually for four minutes— pulsed binaural beats and a flashing background according to two states: relaxed mode at 4hz, and focused mode at 40hz. I had users wear the headphones and an EEG device, close their eyes, and face the flashing screen:
The video below shows a relaxed mode session, as well as the corresponding brain activity of the user. As we predicted, the 4hz entrainment from the p5 sketch seems to encourage ~4z brain waves (ie delta/theta frequency bands):
So that was pretty exciting!
We had also decided to incorporate a heart rate sensor, so that the tempo of the eventual entrainment music could sync to it. Here’s Barak’s clever serial-monitor-visualization of his heart rate:
The fact that the user would enter a dome made it necessary for the headset to be wireless. We purchased a Node MCU for the task, which meant the data would be sent over wifi instead of a serial port. In order to securely fasten the Node MCU to the Neurosky chip, we 3d-printed a little mount:
After making good progress on the headset, it was time to start on the geodesic dome. We purchased second-hand Hubs from a guy in Canada, as well as pretty much every single 5/8″ dowel from Home Depot. It was a big job, so we enlisted some help from my ever-helpful boyfriend:
And then it was off to Spandex World to get some miliskin for projecting on:
For the audio/visual entrainment piece, Barak used a combination of Ableton, an audio synthesizer, and Lumen, a visual synthesizer. Ableton receives heart rate information from our sensor over a midi port, which influences the tempo of the audio, and Lumen receives midi information from Ableton, which influences the frequency of the visuals. Here’s Barak playing with the different templates:
The actual colors would be red and blue for focused and relaxed mode, respectively. According to this paper, these colors encourage the frequency bands (beta/gamma and delta/theta, respectively) that we were targeting.
Yes, we realized covering the dome from the outside looked a little shabby, so we decided, on Ben Light’s suggestion, to use grommets:
More to come on dome development!
The last component was the olfactory entrainment. According to this paper, rosemary and lavender would encourage beta/gamma and delta/theta bands, respectively. We purchased $10 diffusers off Amazon to hack, as well as rosemary and lavender essential oils. Wiring up this circuit was a bit of a mindfuck for mysterious reasons we can’t even explain, but ultimately we ended up using transistors so that only the appropriate diffuser would turn on after the user chose their desired state:
Also notable is that we used our first rotary switch:
But after all that work (and acrylic), we ultimately decided to only go with the relaxed mode—it made more sense in context of the Winter Show. I mean, who would choose to become more alert during such an intensely stimulating environment?
Lastly, here’s a screenshot of the EEG visualization I’m working on for the show:
The canvas expands as the data streams in, which will be saved as an image at the end of each session. There’s also an option to start a new session, which will empty all arrays as well as signal the processing sketch to start over.