My sense is that the author’s experience is very similar to that of most tDCS DIYers – an initial flurry of interest followed by frustration at not knowing if ‘it’s working’. That’s why it’s exciting to see easily replicated protocols for self-testing emerging around the Dual N-Back game that is available for free. http://brainworkshop.sourceforge.net/download.html
We’d decided to try the “accelerated learning” montage that had been developed and tested by DARPA. The best test of the device we could come up with was to play Nintendo Wii Mario Kart while brain zapping for 20 minutes — our performance seemed easily measurable (we would just play the same course, over and over) and a lot less violent. At first I was miserable, my green dinosaur avatar, Yoshi, falling off the track on every hairpin turn and barely finishing the course in 3:30. By the end, though, I was cracking 3:00. Of course, there was no control here, no way to tell whether I was simply learning a new skill, but I was cautiously optimistic.
In the weeks that followed, I stuck to it, undertaking 20 minutes of tDCS four to five days a week. I decided to try to teach myself interactive web design, and whenever I’d run the current through my brain, I’d accompany it with 20 minutes on Code Academy, the teach-yourself-to-code megasite. But after a few weeks, the results I was looking for seemed elusive. I was obviously getting better at coding, but there was no way for me to know what role the electricity was playing. And it was still kind of painful. So I quit, and about two months after visiting Bikson’s lab, my tDCS device is gathering dust on a shelf in my office.
TechKnow: How do you plan on measuring your progress with the tDCS headset?
Erica: So I’m using a brain training game called Dual N-Back. So far I’ve tracked my progress with the game without using the tDCS, and I plan to use tDCS, and then practice the game and see how far I can get.
TechKnow: Are you going to record this information? Do you plan on making it available to other people?
Erica: I plan to track the amount of time I’m spending using tDCS and how well I’m performing in the game to see what is correlated.
Jesse interviews Nathan Whitmore, creator of the open-source project OpenBrainStim, an affordable alternative to commercial transcranial Direct Current Stimulation (tDCS) devices. Nathan tells us how the project got started, how the “DIY-tCDS” community has grown, and how you can experiment from the comfort of your own home.
Brent Williams of SpeakWisdom just published a checklist for DIY tDCSers. Links at bottom to full list.
DIY tDCS Safety Standards
As a potential or current do-it-yourself tDCS user I agree to the following:
1. I will, if reasonably possible, seek out a medical professional for tDCS advice, treatments and follow-up.
2. If I have cranial scar tissue, an implant, or other unusual medical condition, I will seek clearance from my doctor before using tDCS. If I have a seizure disorder I will refrain from using tDCS or use it only under direct supervision of qualified medical personnel.
3. I will not, under any circumstances, directly connect a battery to my head. I understand that I could greatly exceed the maximum 2 mA current limit used by tDCS researchers, possibly harming myself in the process.
That’s what Jared Seehafer did. He’s a 28-year-old medical device consultant in San Francisco who heads the group.
He made his own tDCS machine using an elastic headband and a couple of electrodes. It’s powered by a 9-volt battery and produces 1 to 2 milliamps of electricity, approximately what it takes to light one small LED bulb.
Regarding the transients at turn on, that is a circuit issue. So to remedy, it is easy to add an LC filter at the output see picture below for new schematic. The LC filter acts to dampen any transients. Bench testing shows the ramp up to be 500ms, which is plenty to dampen any turn on pulses, but unfortunately not enough to prevent any flash that occurs with certain montages. At mouser.com, the L can be 22R105C and the C can be UKL1E100KDDANA.
Ramping capacitor – possible problem
Yesterday i was building some tDCS with LM334 and try for first time use ramping capacitor. When i test device with load (5KOhms) all was ok ramping when i turn device on and ramping down when off. But when i change load (5kOhms potentiometer) during stimulation (testing) it create current peak up to 5 mA. I test it with few different capacitor and behavior is always the same (only different value of peak and the time to return to normal ). Device without capacitor work without problem. In result of this i use instead of capacitor serial load ( linear potentiometer 100kOhms ) allows me to do manual ramping (0,07mA to setup current).
My question is can anybody test this capacitor problem maybe i do something wrong, bad multimeter etc.. . If this problem is real, it’s a very bad idea to use capacitor for ramping in use the resistance change is not too quick but still can cause pretty high current peaks.
Above is a schematic for a simple tDCS circuit that will supply 1mA. The CRD (E-102) maintains a 1mA regulated current to the head (between the Anode and Cathode). The E-102 can be purchased at www.mouser.com. Two 9V batteries are better than one, particularly if you have a less than perfect electrode-head interface, and it will last much longer without the need to change the battery; also the CRD has a 1V-2V drop so the full battery voltage is not present at the Anode. In using the CRD, you have a two pin regulator instead of a three pin regulator and a resistor for the LM334, which means simpler construction.
Brent Williams of SpeakWisdom (we met him earlier on the blog) has started a YouTube tDCS series. This is his second in the series. This is an excellent overview of the basic components of tDCS, however, Brent does not recommend you actually build
and use a resistor-based device. Brent mentions that upcoming videos will demonstrate how to build a current-regulated device.