Time to do a catchup on a bunch of bits.

Weak Field Magnetic Stimulation

I’ve hooked up an assortment of coils, ranging from speaker voice coils, to induction motor coils, to relay and solenoid coils and driven them with a range of MWS generated signals, at field levels up to 50 milliGauss (5x the level suggested for the Shakti). As I’m not experiencing anything that requires therapeutic application just now, I’ve been focused on changes to perception. I’ve found that photically induced visuals provide an excellent indication of interaction between areas of the brain – notably the effect of audio on visuals. I’ve found that the magnetic fields have similar effects to audio, but more subtle. Used without an AS track, I have been able to sense nothing whatsoever from magnetic stimulation. There’s a lot more experimentation to be done here, but I’m not holding my breath for great results.

Laxman Goggles

With the failure of the left-hand frame of my goggles, I decided to see if there was any hope for repair. I’m blown away by how beautifully they’re made – a fortune must have been spent on tooling – but they are not repairable. Everything is moulded into place and removal of the edge-lit diffusers is fatally destructive. Joining the sets of LEDs is a fine section of flexible circuit board (just like that you can see running between frames on MindPlace and other glasses) moulded into the bridge. Unfortunately such material is not going to withstand a lot of bending, twisting or stretching.

My Laxman has had a lot of use, much of it by users with less than a light touch. As I was not present at the time of failure, I can’t really know just how fragile they are, but I do feel obliged to warn Laxman goggle owners to treat them gently.

I’ve also been a little baffled by the fact that Laxman goggles work with a Procyon, but Procyon glasses don’t work with a Laxman. I’m hoping to have more information on this soon.

An Audiostrobe Alternative

In the course of experimenting with LED drivers and ways to create dramatic visuals, I’ve found that LED glasses can be driven quite effectively with plain old audio. The headphone levels on many consumer devices are inadequate, being designed to drive high-efficiency lower-end earphones, but some powered speakers that also have a headphone socket will drive the glasses quite well. The headphone output from my little Behringer mixer works superbly.

This may seem a little bit like, “who cares?”, but freedom from the constraints of the Audiostrobe signal format is a wonderful thing, as anyone who has used the programmable light capabilities of a Proteus or Procyon can attest. With Audiostrobe you’re limited to whatever signal you can modulate a 19.2kHz tone with. Driving with pure audio means you can eliminate the 19.2kHz carrier, which, notice it or not, is right there through the stimulation audio. You can also eliminate the pulse width modulation (PWM) frequency that is often used for LED brightness control. Best of all, you can use any waveshape you can create to drive the LEDs. Herein lies the answer for those who seek to emulate the legendary pRoshi.

MindPlace glasses include diodes that protect against reverse connection of the LEDs. I do not know if this is so for other glasses, so I cannot guarantee the survival of other brands. This arrangement also lacks current-limiting resistors, so some audio sources may be capable of exceeding the maximum current rating of the LEDs. If you want to experiment with this idea, always start with the volume set low and gently increase until the LEDs are no brighter than they are with the mind machine. Anyway, this is not approved usage of the glasses or the audio device, so on your head be it!

Obviously you’re not going to want to be listening to the light drive signal, so this exercise assumes that there is a second device available for audio – a second soundcard in a PC, USB sound device on a laptop, or even just another MP3 player. I’m thinking some great fun could be had with one of these multi-channel soundcards…

In real life, when I decide to implement this in the stimulation helmet, or wherever, I’ll be adding a driver, probably just a single transistor and a few resistors, between audio device and glasses and powering the driver/glasses from a separate supply.

Tactile Stimulation

In the course of exposing myself to the fields of everything magnetic I could find, I laid my head on the metal diaphragms of my cheapy Genius computer speakers whilst playing a solid 7.8Hz isochronic beat. Apart from the interesting feeling of have the audio arrive via my skull (there’s a couple of commercial devices that do this – the Neurophone and another, the name of which escapes me just now), the vibration against my scalp was extremely pleasing. These trials were done with a pair of glasses providing a complex visual pattern, and with this particular setup the visuals went wild – sound + magnetism + vibration, applied just outside the visual cortex definitely affects imagery. Obviously this is almost completely useless information, as I have no idea which variable, or combination thereof, led to the effect, but it’s fun anyway.

Speakers are not intended to have the motion of their diaphragms restricted and doing so will result in heating of the voice coil. Some diaphragm designs are much more fragile than the rubber mounted foil in my speakers, and even if no damaged is evident, centring of the voice coil in the permanent magnet can be ruined. So, again, try this at your own peril (I wouldn’t do it with a pair of speaker that I wouldn’t be willing to throw away).

That’ll do for now!


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