From a comment to the blog. Doc Johnson shares this beautiful DIY tDCS build. Thanks Doc!
I’m personally just beginning experimenting with TDCS, and as an avid DIYer, I built my own. The open designs I’ve seen seem to be a little short on features (particularly a fail-safe over-current protection), so I decided to use my background as an Electrical Engineer to start from scratch. It might be useful for others who are interested in building their own.
The design incorporates a feature that trips something equivalent to a circuit breaker if more than about 4.8mA of current flows through the electrodes. It should never happen based on the current regulator design, but I’ve seen too many pieces of silicon short out in a way that would be dangerous in this situation. I finished testing the design this weekend, and am quite happy with it. All told, the parts are about $20, not counting the hours spent designing, building, testing, redesigning…
The design and links for how I built the circuit board are located at https://www.diligent5.org/?p=1993 I built it using surface mount components because I like the tighter resistor tolerances available, but theoretically the components (or something equivalent) are available as through-hole components for the less adventurous. Cheers, Doc Johnson