DIY tDCS Safety Standards | SpeakWisdom

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.

via DIY tDCS Safety Standards | SpeakWisdom.

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Hacking The Brain With Electricity: Don’t Try This At Home | NPR

Jared Seehafer wearing his homemade tDCS device.

Jared Seehafer wearing his homemade tDCS device.

Courtesy of Amy Standen

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.

via Hacking The Brain With Electricity: Don’t Try This At Home : Shots – Health News : NPR.

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A little less Simple DIY TDCS circuit using CRDs | Insight

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.

via Insight, a growth project driven by tDCS: A little less Simple DIY TDCS circuit using CRDs.

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tdcs LM334 Ramping capacitor – possible problem

Petr, whose first language is Czech, asks…

12.3 2013
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.

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Insight, a growth project driven by tDCS: Simple DIY TDCS circuit using CRDs

 Read the full article here.

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.

via Insight, a growth project driven by tDCS: Simple DIY TDCS circuit using CRDs.

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tDCS – Building a Resistor Based tDCS Device

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.

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Another DIY tDCS Video

Hard to imagine how he’d have learned enough about tDCS to build a device, but have gotten the (typical) montage so wrong. Placing the cathode over left DLPFC and anode over right orbital is exactly the opposite of what you’ll find in most studies related to both depression and working memory. He doesn’t go into how he’s constructed his electrodes at all. Anecdotally, it is interesting that the reverse montage made him feel angry and depressed.

 

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Weekend tDCS Insights – Chi & Snyder, SpeakWisdom, Carlo Miniussi

Some very excellent tDCS-related documents came to my attention over the weekend. I’m pretty sure I’d looked for at least one of them before, but that it was behind a paywall. I’ll provide links to the pdfs here, but suggest that (as has happened elsewhere on the blog) pdf links frequently go bad so ‘get em while they’re hot’.

Brain stimulation enables the solution of an inherently difficult problem (pdf)
This is the paper by Alan Snyder and Richard Chi that is frequently referenced in ‘unlock your inner savant’ articles on various pop-sci sites. (See also) Spoiler alert! Gives the answer to the ’9 dot’ problem and once you’ve seen it it will be impossible to discover how ‘savant-like’ you are (at least according to this test).

ninedot …we applied cathodal tDCS (1.6mA) at the left anterior temporal lobe (ATL) together with anodal tDCS at the right ATL for approximately 10 min… None of the 22 participants in the main experiment solved the nine-dot problem before stimulation. But with 10 min of right lat- eralizing transcranial direct current stimulation (tDCS), we found that more than 40% of participants could do so.

speakWisdomTakeapartDr. Brent Williams, at his SpeakWisdom blog, published another excellent tDCS post updating his DIY device, and adding a .doc that outlines his recommended (For Discussion) protocols for depression, ‘Savant Learning’, memorization, and chronic pain.
His protocol describes directions for use with either his ‘User-Built tDCS Research Device’, or the ActivaDose II.

Transcranial Magnetic and Electric Stimulation in Perception and Cognition Research (pdf)
This is a fascinating paper (Carlo Miniussi et al) that brings us up to date (2012) on applications of tDCS, TMS tACS (transcranial alternating current), and tRNS (transcranial random noise stimulation), especially in relation to cognition and learning. What really caught my eye was this entry about tRNS…

 tRNS consists of the application of a random electrical oscillation spectrum over the cortex. tRNS can be applied at different frequency band ranges over the entire spectrum from 0.1 to 640 Hz…They applied tRNS to the visual cortices of healthy subjects and observed a significant improvement in the performance of healthy subjects in a visual perceptual learning task. This improvement was significantly higher than the improvement obtained with anodal tDCS…

And that folks, is how a weekend disappears down the rabbit hole!

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The Open tDCS Project

Update 7/2/14 First of all, thanks Z for pointing out the two schematics that are now considered dangerous, in the sense that they could lead to an initial ‘zap’ and possible burn.

As I’ve mentioned earlier, I myself am not an electronics person. The notion of ‘Open tDCS’ was to develop an excellent device through Upverter (or similar online platform), that anyone could then order directly from a Chinese manufacturer (thereby circumnavigating any regulation issues etc).
We have yet to find an engineer to lead and build the design team and my thoughts about why are simply that people are too busy, or that they see a possible financial gain for their own device somewhere down the road. Considering the original post/Upverter account is a year and a half old, it seems unlikely we’ll find someone, but you never know!
——————————
Upverter is an online platform that allows for electronics to be designed, parted, and built. As I understand it, once the design is fixed, you shop for parts – inside of Upverter, and then submit your project (to Upverter’s Chinese partners) to be built. I’d mentioned Upverter on the tDCS subReddit a few times. I was hoping to pique the curiosity of the engineer types that had designed and built their own tDCS devices… Crowdsource the design, and then anyone can order one!

What happened was I got an email from Eric Evenchick, a ‘customer success / hardware engineer person’ at Upverter! Eric had seen my post and written to help. He waived the team fee, set up the project and ported the OpenStim Arduino-based tDCS design, by ohsnapitsnathan (Reddit handle).

I hope I didn’t step on any toes by collecting these schematics to one place. I wanted engineers to be able to see quickly how other designers have thought about building their devices. If you’re an engineer type interested in tDCS please join our Upverter team.

It feels silly to put it this way, when the very nature of Open implies extreme democracy, but here goes… Here’s my vision of an Open tDCS project.

  • Build an Upverter team
  • Design, part, and prototype a minimum viable tDCS device
  • Working with an online ‘cognitive test’ site, build a protocol for measuring the effectiveness of tDCS

Later on we could develop a multi-channel device, and maybe this is just a fantasy, but if it could interact with the internet, researchers could design tests and collect data non-locally. How cool would that be?

The rest of this post will attempt to collect in one place the various schematics I’ve seen for DIY tDCS devices.

I called this one Imgur earlier on the blog. It comes from 55tfg7879fe42e345 (Reddit handle)

tDCS by 55tfg7879fe42e345

tDCS by 55tfg7879fe42e345

 

brmlab our Czech friends

brmlab-tdcs

The Focus device. (pdf)

Focus V 1

Focus V 1

And then the more advanced, programmable tDCS devices. OpenStim

OpenStim

OpenStim

Open Stim Multi-Channel

OpenStim Multi-Channel

OpenStim Multi-Channel

Shawn Nock Version 2

Shawn Nock Version 2

Shawn Nock Version 2

If you know of a schematic I missed please let me know, and even if you’re not an engineer, consider joining Upverter and ‘Following’ our project.

 

 

 

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tDCS – Building Research tDCS Units « SpeakWisdom

This bubbled up today. He explores some choices he made in building his DIY kit in a series of blog posts on tDCS.

Just to see how easily it could be done, I built a couple of tDCS units for about $30 each using common parts. The meters were purchased from EBay for about $7 each and all the remaining components came from a local Radio Shack, including the case, voltage regulator, resistors, etc. The tDCS units feature a potentiometer to make it possible to adjust current for treatment specifics or pad variations.

20120902-214144.jpg
(Two tDCS units built in about 3 hours for well less than $100)

 

via tDCS – Building Research tDCS Units « SpeakWisdom.

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