Another Project – TDCS Controller

CAVEAT: The design described here has fatal flaws. I’ve since re-designed it, and have left this here as a way to document the process and share the realities associated with designing even relatively simple things with whoever might read it. The current design is available here.

I don’t seem to be able to function well without some kind of project. Usually I have several waiting patiently for my attention. However, at the moment all my current ones require either time, money, or energy I just can’t afford to give. I have a coding project to finish the user interface for the antenna analyzer I designed and built. But that’s at a point where the interesting work is done, I’m stuck on something that should be easy, but there’s something I’m missing. I’ve been using the project to get better at C++, and have run into issues that probably stem from my poor understanding of class objects and their use in my implementation. I’m out of ideas, frustrated at my inability to figure it out, and just can’t convince myself to re-attack it. I’ll tackle it again, but not until I’ve quit being frustrated with it.

Many of the other projects require large enough chunks of money to move to the next step that they have to sit and wait for that arbitrary future when I’ll have enough cash to make more progress. Sometimes incremental progress isn’t really viable, so things just sit and collect dust. The rest (like my writing projects) require motivation and energy I just don’t have at the moment. I don’t have a good excuse other than I’m burned out on them. They’ll sit until I change how I feel about them.

I needed a project I could work on that didn’t take much creative energy, would keep my mind active, and that I could reasonably finish with the small budget I get to spend without having to impact the household finances. Thinking about it, I decided I’d try designing and building a Transcranial Direct Current Stimulator (TDCS). I’ve been seeing reports on the technology for years, and have watched agencies from DARPA to the Air Force research lab study it and demonstrate measurable effects. I’ve been curious to try it, but the controllers are either expensive, or I question the safety features in the slip-shod designs of products coming from places like China or fly-by-night hobby shops just trying to make a quick buck.

The basic concept behind the devices is really simple. The circuit applies a voltage just large enough to induce a small current through the head. Done right, the current is way below the threshold for causing any physiological damage. It can tingle or sting some, will probably leave a metallic taste in your mouth, and might cause a perception of a brief flash of light, but that’s about it. The theory behind its effect is that the small current creates a marginal potential in the brain that modulates the much stronger natural electrical signals already there. That modulation is thought to help selectively dampen or enhance those natural signals.

TDCS has shown clinical significance treating some forms of depression, anxiety, and chronic pain. It had been shown to increase user focus and accelerate learning. There are claims all over the place that it does everything sort of washing the dinner dishes for you. Some claims are backed up by robust research, others are anecdotal or even outright crap. I’m mostly interested in trying the more researched claims associated with depression and focus.

In particular, I’m interested in seeing how effective it would be against my particular variety of mood disorder. However, I’m not interested enough to buy a good device and not willing to risk attaching electrodes to my head driven by a device built and sold by Fast Eddy in his garage. I trust myself and the things I build in my garage. Not so much things built in other people’s garages.

So, with that in mind, I’m going to design my own. Over the next few posts, I’ll share the process and details. So without further adieu, on to Part 1 – Design.

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