Transcranial Magnetic Stimulation project - part 1

[Transfusions]

Do we have any other method from using SCR?

[bkraz333]

@Transfusions A bank of MOSFETs would also work and allow the current to be stopped before the capacitors have discharged.

[Films4You]

Electroconvulsive therapy by another name, an electric current is induced in the brain by these systems

[bkraz333]

@theemusic92 The most dangerous aspect is the charge stored in the capacitor bank (can cause a very nasty shock). Single-pulse TMS has been done on humans for decades without any lasting effects.

[TeravoltOrg]

I like your SCR clamp

[pgqneto]

Congratulations! I've been researching about how to build my own TMS stimulator. what is the clamp on the SCR for and how much did you pay for it? is it possible to make rTMS, like 20 pulses per second?

[bkraz333]

@pgqneto These hockey-puck type SCRs require external clamping pressure to operate properly. I am using a woodworking clamp, which is probably barely adequate. It should be clamped down with heavy bolts -- the datasheet lists a minimum and maximum clamping force.

[bkraz333]

@pgqneto rTMS should be possible, but I don't want to try it myself. It would need a much larger capacitor bank, and a MOSFET or similar switch that can be turned off mid-pulse.

[pgqneto]

@bkraz333 Thank you Sir. Do you know what is a pulse capacitor? I saw a video of a guy that is launching a washer with an old Magstim. He sent me pictures of the Magstim inside. It uses two 50uf/5Kv General Atomics pulse capacitors. they must be very expensive.

[bkraz333]

@pgqneto It sounds like marketing jargon. Use any low-ESR capacitor with sufficient capacitance and voltage ratings.

[masteranza]

any updates? Did you increase the inductance? I really wonder about the effects... I assume that you probably want to buy yourself a super-brain through stimulation.

[DrInductor]

Are you completely sure this is safe? I wouldn't want to hold this thing close to my head because I do believe these things have triggered seizures in the past.

[puddingpimp]

It looks like you have the two coils wired in series, wouldn't it be better to have them wired in parallel, but inverted polarity, to maintain the magnetic lensing effect but reduce the reactance, so as to increase the discharge rate, and presumably the magnetic flux density?

[bkraz333]

@puddingpimp In my current design, the pulses are too fast to cause decent neuron stimulation because the overall circuit inductance is probably too low. Putting the coils in series will increase inductance and lengthen the rise time of the current pulse.  I always thought that minimizing the rise time would be desirable, but apparently, the neurons need time to depolarize, and this requires more careful pulse shaping

[inflivia]

haha. You made your own TMS unit? I <3 you Ben.

[fettfettmerafett]

Wow... Watch out for the government!

[Alectr0n]

Try and stimulate the pleasure center of your brain, then you can safely divorce your wife.

[artifactingreality]

lol i love the idea that you're building medical equipment in your house and then testing it on yourself. I'm looking forward to part 2.

[TheCrazyInventor]

Damn, this sounds really scary. Putting some random magnetic field on your head and watch what starts malfunctioning... I've seen this on the discovery channel (or was it discovery science?). A doctor would stimulate a woman's head with a similar looking device as yours (but nicely packaged of course, but you could clearly see that there where 2 coils in there). Stimulating her head, made her arm suddenly move against her will. Sounds scary to me but I'm interested to see how this will turn out.

[Galfonz]

That sounds like one of those "I can't believe people did that" things. Similar to early playing with X-Rays and radio activity.

[jeriellsworth]

Neato!

[deathsminion25]

Draw a picture before and another after using it and video tape yourself doing it.

[oisiaa]

You are the closest thing to a mad scientist that I have ever seen! (That is a good thing BTW).

[cpnnpr]

Could you immerse the coil in liquid nitrogen to reduce the inductance a useful amount?

P.S. love your videos!

[mmavipc]

shit makes you go crazy?