What is going on

I started this blog to keep a sort of running list of what projects I have going on and my progress on each of them. Instead of doing that, I’ve been working on the projects and ignoring the blog.

My main project right now is the Seizuredome. The “dome” part is an icosahedron made out of electrical conduit. Five of the faces of the icosahedron are left off, and it rests on the ground on that side, forming a sort of dome. I used the construction techniques from Desert Domes to build the frame, but the process is essentially flattening the ends of the pieces of pipe and drilling holes in them so they can be held together with bolts. There is a picture of the completed dome frame in a previous post. That frame will be covered with mylar “space blankets” to provide a reflective surface.

The “seizure” part of the dome is a little more complicated. If you close your eyes and look at a bright light, you can still sort-of see the light, as a red glow through your eyelids. If that light pulses in the 5-20Hz range, you would expect to see the blinking through your eyelids. Instead, most people end up seeing colorful patterns, like swirling fractals, tye-die designs, spiderwebs, and such. What happens is that the blinking signal is close enough to the patterns of electrical activity in the brain that it can drive the dominant frequencies of neural activity to synchronize with it, resulting in hallucinations and mildly altered states of consciousness. You can buy goggles with blinking lights in them, or make your own devices, which will allow one person to do this. I’m building a photic driver for multiple users.

The Seizuredome will have a bright red strobing light in its center. This light is made of 20 1-watt red LEDs mounted on the surface of an aluminum icosahedron. Each LED is driven by a constant-current driver, which is controlled by a TLC5940 LED driver chip. The TLC5940 chips are controlled by an Arduino. Power for the whole thing is supplied by a LM7805 supply with a beefy pass transistor. That light will be hung inside the reflective dome, illuminating the inside. Since the light is suspended inside a reflective dome, there will probably be no place inside the dome that isn’t strobing red, so users inside the dome will be able to see the psychedelic show by entering the dome and closing their eyes.

That still doesn’t really answer why I called it the Seizuredome, though. I turns out that some people are photosensitive epileptics, but don’t know it. Strobing lights of the frequencies most likely to cause seizures by interfering with neural electrical activity are rare, and don’t usually last long enough to trigger seizures. As a result, it’s possible for someone to grow up without ever seeing a blinking light that is intense enough for a long enough time to cause a seizure.

Until now.