OpenStim is a community that aims to develop a magnetic brain stimulator which you can build and use in your own home.
The technique is known as ‘transcranial magnetic stimulation’ or TMS. In essence, TMS is a powerful computer controlled electromagnet that sends focused magnetic pulses into the brain.
The magnetic field induces a current in the neurons, which then become stimulated as a result.
This can be used to alter the brain in specific ways, either activating or deactivating certain areas of the cortex.
This is often used for neuroscience research. For example, if you suspect that a certain brain area is involved during a certain task, you can alter the function of the brain area and see if participants perform the task any differently.
Existing research has used this technique and has shown that stimulating certain areas improves mood or, in some instances, cognitive performance.
The OpenStim project states their aims as:
1. Create a community that designs the core technology for a safe, highly functional, inexpensive, efficacious noninvasive transcranial magnetic stimulator (TMS) device for stimulating the central nervous system.
2. Facilitate experimentation and exchange of ideas, on the topic of modulation of brain function in a variety of people and contexts, so that we can learn more about the neural circuits mediating our subjective experiences, and improve mental functions (aka hacking your brain).
Although they aim to build a “safe” device, I can’t actually see anything on their site which specifies exactly what they define as safe.
In the research, TMS most commonly refers to specifically designed high powered electromagnets that pump out about 1-1.5 Tesla of field strength in millisecond bursts.
This is very powerful, although because of the thickness of the skull and the need to use only the most focused part of the magnetic field, it is only enough to reliably discharge a few centimetres square of neurons just below the skull.
However, a significant danger is that with enough pulses, a seizure is triggered.
Most of the protocols in the TMS literature and research centres are designed to avoid this. When these limits are adhered to, TMS is very safe and no long-lasting effects have been found.
However, even if you make sure you keep within the accepted ‘safe limits’ for TMS stimulation, with home-built kit you are less likely to be sure that your equipment is genuinely doing what it is supposed to.
In other words, builder beware! Your brain is fragile, so make sure you know the risks before altering it in anyway.
Link to OpenStim project.
Mind Hacks 
I have seen no reference on the “OpenStim” page indicating the necessity for a “Thyristor to regulate current flow from the capacitor. This is an important element for efficacy and safety.
I have seen no reference on the “OpenStim” page indicating the necessity for a “Thyristor to regulate current flow from the capacitor. This is an important element for efficacy and safety.
What about TransCranial Brain Stim?
Youtube sez it’s unavailable – Where can I dLoad?
What do you think about usinig the Beck magnetic pulser for that purpose?
So what’s the next step?
…to make steps progress in terms of construction cost, simplicity, ‘stearability’ (eg, Raster scan) and safety, I assume we need to move beyond the basic butter-fly design, and a single pulse train… but! use its base principle of enhancing the spacial gradient field?
thoughts: – Can an array of carefully timed, sub loops do this? Like a butterfly with 48 wings in a concentric AND overlapping array.. instead of 2…?.
if each “wing” can each contribute to the action potential (say 60mV) target, within a few mS..then they should be able to work together? thus avoiding a huge dI/dt (huge thyristor) and instead use an array designed with smaller sub coils (wings)?
If u agree in principle.. does Anyone have access to a Maxwell3D or HFSS copy to quantify this?
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