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What do people think about tDCS? Is such a thingy easy to make? Answered


This is by all reports a safe device and has been shown to be for years. However, the danger will be from people who: a) decide that more is better and give themselves much more current than is safe and/or who b) decide to not just use electrodes on their skin but want to find a way to put the electrodes inside them, thereby potentially disrupting their heart rhythm or causing brain damage. More is not always better and the appropriate current is safe if you put the electrodes ON your skin, not in your skin.

I wrote an instructable detailing a simple design for a tDCS device. Hopefully you guys find it useful :)


I'm not saying that one way or the other is wrong. I would definitely not recommend this sort of thing without working knowledge or workable research. I think that in the next ten or twenty years, we will see this more heavily used in colleges across the world.

Actually, my girlfriend wants to do a paper on this.
I'm not against trying it, but I'd rather put the cap together myself since she will make her own if I don't. So this links are a great starting point. I wouldn't mind seeing personal building plans.

She's interested in exploring the speed learning. She has a list of professionals she wants to look into. We're starting with learning a foreign language since it isn't difficult to figure out where the brain records language.

How is it going for you guys? Hablas en español? ;) hope to hear from you

I've followed the new emergence of tDCS for about three years and am about to start trying it and make an instructable following my experiment. However I have this to say so far :
1. No you shouldn't try this at home! It's dangerous. I may be about to cripple my own brain and I know it.
2. I suffer from severe depression, PTSD, anxiety and migraines and am only trying this as another attempt to relieve symptoms which are in themselves very dangerous. You probably have more to loose than I have.
3. The circuits and components used are off the shelf and rather cheap except one : your brain. If I've made a mistake in my circuit or there is a faulty component or perhaps the research is wrong then I can do more harm than good.
4. I intend to make a minor case study on myself to evaluate any effects which is stupid because as my own research subject I am very biased.

I wish you good luck in your experiment. Being someone who also suffers a great deal from depression and anxiety, I understand completely your desires to test this sort of technology, and I hope you can find some relief.

I am excited for you! And I look forward to hearing about your experience.

I think its promising. Use ohms law and do some research, they are easy enough to make. Usually 1-2 mA of current.

This certainly is NOT a case of "using Ohm's law" - screw this up, you're into serious problems.


Yes, it is. Get the voltage right, and the desired current, and duh, Ohms law. The medical machines put out...ummm...voltage and current.


What correction do you make for skin resistance ? Dry skin >>1Meg Ohm, Wet skin <<1K

"Ohm's law" will kill you, when your circuit, which passes 1mA, into a resistance of 1Mohm attempts to pass 1000mA through 1k.

DON'T encourage people to make their own equipment to inject current into their bodies, unless THEY are qualified designers, and understand the very grave risks.

And don't encourage people to think that just applying Ohm's law is sufficient.

dry skin 1M ohm
9volt battery 9V

9= I * 1,000,000
I=9/1,000,000 = 0.000009A
so the current is 9uA This is very safe.

The human skull has a resistance (roughly) of about 12.5k ohms.
I=9/12500 =0.00072A
This is 0.7mA still a factor of 3 lower than the safety level per cm squared.

(Anyone wanting to make one, I wouldn't take my values for gospel, and would use a suitably high potentiometer in series to your current regulator, with an accurate current meter to obtain the correct current)

Well, I'm more optimistic that steveastrouk that this can be done pretty safely at home.

But for reals, don't just rely on Ohm's law! Get yourself a real current regulator, jeez. They're like 50 cents, and this is your brain we're talking about.

Look for something like an LM317. Read the datasheet carefully, learn how to use it properly. You should be able to set it to deliver 1-2mA, and it'll adjust internal resistance to deliver a constant amount of current, whatever the resistance of your skin.

There are a number of reasons why one would want to pump current through their brain. I think it would be pretty nifty.

Transcranial Direct Current Stimulation or tDCS is a growing field of research with a potentially wide impact. They have already found numerous applications in the treatment of issues arising from various types of brain damage. In healthy brains tDCS has been shown to improve functioning in a wide range of tasks depending on the part that is being stimulated. The amount of current applied, 20mins @ 1mA, is not enough to cause any permanent damage. The following papers are studies of the effects of current applied to different parts of the brain.

If you do a search on that site for "transcranial direct current stimulation healthy improves" you can find more papers on the subject.

The device itself is relatively simple and I think it would not be incredibly challenging to build one. I think the cap would be the most difficult part, just due to the number of electrodes and accurately mapping the locations. The charts for it are on the net though. If you want to mess around with it, two electrodes would probably be sufficient. If you really want to study it, a cap based on the 10-20, 10-10 or 10-5 EEG standard would likely be more useful and can be purchased for $250-$600. If you are building one yourself, here is a link to a paper that describes the Modified Combinatorial Nomenclature (MCN) System based on the International 10-20 EEG Standard. http://www.acns.org/pdfs/ACFDD46.pdf

All that being said, this is an area where one experiments at their own risk. I would think that this is something that should only be done if one is very familiar with the brain and the various functions of the different regions. There have been negative side effects. However, the effects, both positive and negative, are relatively short lived; lasting anywhere from a few minutes to a few hours. I've never seen any reports of permanent damage at the current amperage. If done improperly, or properly in the wrong spot, you could temporarily blind yourself or cause any number of other potentially unwanted strangeness. That is the worst I've read about though.

This isn't about a couple of wires, a resistor and a 9v battery.

Its not easy to make. You need to know a lot about electronics to do it safely. This is your brain you are thinking of messing with. Do it wrong, and it may kill you. It can certainly cause you to suffer a fit.

It is relatively easy to make, as it is a DC currency regulator circuit. Voltage is not the issue, it is the current that is flowing through that must be regulated. If you plug your head into the wall then you're a total idiot, however at the levels talked about this will most definitely NOT kill. It is recommended that the brainstem is not stimulated, just incase of arrhythmia or resticted breathing.
There is talk of some bad reactions and psychosis from a report in the 1960's, but this is also in reference to electroshock, and that was pretty much like having a car battery charger across your head.
Also the time referred to for the length of time damage could take effect in such studies was repeatedly over several hours. tDCS is used for 10~15mins with several days rest inbetween, and it's effects (stimulating the polarised region) only last for 1~2hrs.

The limit ascribed by the neurology is 2mA (0.002Amps) per cm^2 (this is a value for applying directly to the brain). However, the studies by Dr Paulus etal recommend a value nearer 1mA (0.001Amps) per 35cm^2. This is several factor below the safety margin, and in their studies, only half of that current was getting to the brain itself due to the resistance of the skull, flow through the skin/fat etc. If you are taking a 9v battery and attaching it to you're head through a couple of 2 pence pieces then you are asking for trouble. A proper current regulator should hold a steady current in a range of 0.5~1.2mA regardless of variation in resistance across the cranium.

Studies on rats suggests that well above 2mA/cm^2 then lesions will form- this is how electroshock therapy worked essentially, generally targeted regions were lobotomized. Voltage has been shown not to be a major issue in brain stimulation, however I shall not be attaching my head into the wall anytime soon.

tDCS is already used for the mentally ill, parkinson's. The US army (maybe UK too...) also uses it as a tool to speed learning, and the case for accelerating learning of physical and cognitive activities is very strong.

I'm planning on making my own tDCS machine, so I'll put my results up once it's made.

Why would you want to inject current through your brain ?


Well, electro shock has been used for years to treat severe depression but it is administered under physician supervision.