According to the US Department of Defense, electricity can turn beginners into experts—anything. The application of current to the brain — known as transcranial direct current stimulation (tDCS) — has received funding from DARPA, the US Department of Defense, and more. And you can build your own with about $10 in parts, simple tools, and some soldering experience.
tDCS supplies a small current from the 9V battery to the brain. It turned out that this stimulation enhances human cognitive abilities. (listen to an episode of Radiolab from New York called «9 Volt Nirvana» if you’re skeptical) . Applying this current to various parts of the brain can give users temporary (and sometimes even permanent ) cognitive improvement. Studies show that tDCS also helps with depression, anxiety, and helps with meditation. The best-known part of the brain — the so-called F3 area — offers up to 40% improvement in certain learning categories. Unfortunately, the long-term effects on neuroplasticity, brain function, and more remain unknown.
The path to brain enlargement remains fraught with dangers, both from your ability to make mistakes and from the unknown long-term consequences of artificial nerve stimulation. Use this guide at your own risk! I can’t stress enough what users are showing the highest degree of security when creating your own tDCS devices. Please read the Electrode Placement section at the bottom of this article.
Can it kill you?
In the 1960s, a US Navy sailor experimented with a 9V battery — he accidentally pushed negative and positive electrodes through the surface of his skin and connected them to a 9V battery. As it turns out, blood (which contains iron) offers very little electrical resistance. As biological beings, our bodies conduct electricity like a circuit. Many of our internal organs receive electrical current from our brain. DC current can disrupt this signal, causing heart failure.
In addition, we know nothing about the long-term effects of tDCS on human physiology. While the electrical current of a 9V battery is quite low when applied to the tongue, internal application is lethal.
Step 0: Intimator MK. I design
The tDCS device we are building in this tutorial is the Inthinkerator MK. I’m from Reddit /r/tdcs user Kulty. Kulty’s open design allows us to borrow and modify it.
From my point of view — as an amateur-amateur — the design looks good. It includes short circuit protection and is safer than other commercial devices such as the Foc.us (our Foc.us review). With proper assembly technique, the risk of a short circuit is very, very low. Keep in mind that the design comes with no warranty and could potentially set your brain on fire — you have been warned.
Step 1: Required Parts
- toggle switch
- 2x 3.3 kΩ resistor
- Resistor 1 kΩ
- Resistor 680 ohm
- 500 ohm. Potentiometer
- Potentiometer 5 kΩ
- White or blue LED
- 2N3904 NPN transistor
- Project box
- Red banana jack
- Black banana jack
- LED Frame
- 9V battery clip
- Potentiometer knob
- Battery 9V (I suggest battery)
- Banana connector compatible wires
The total cost of parts should be around $10-$20, but you will also need some basic tools as you would with any electronics project.
Step 2: lay out the layout
Test the circuit first on a breadboard to determine if the parts are good and if the schematic is correct — you won’t need all the parts. Note that we are using a 220 ohm resistor as a test load to simulate skin contact.
The exact holes the pieces are inserted into don’t really matter — focus on completing the diagram. If you’re not sure you want to use layout, be sure to check out our Beginner Skills for Electronic Projects for leadership first.
When done, you can attach the battery connector to your 9V battery and connect it to the positive and negative rails on the side of the breadboard. If everything works, you should see the LED turn on. If that doesn’t work, reanalyze the circuit to make sure it’s wired correctly.
Step 3: Submit your project
Now take the project window and mark the location of the following components using a marker:
- Positive banana plug (red)
- Negative banana plug (black)
- Trimmer potentiometer
- toggle switch
- NPN transistor
- Potentiometer
- Project box (of course)
Step 4: Drill holes
You will need to drill six holes. I suggest drilling from the inside of the case rather than the outside. Also, make sure your components actually fit before moving on to the next hole.
- Holes 1 and 2 : Drill two holes in the top of the box. They need to place the screws on the cathode and the anode banana jack. About 1/4 to 1/3 inch will do.
- Hole 3 : Drill a large hole about 1/2″ in diameter to accommodate the LED light and its chrome body.
- Hole 4 : Drill another large hole, about ½ inch in diameter, in the center of the box to place the potentiometer.
- Hole 5 (not drilled in picture): Drill a small hole about 5/16″ in diameter to accommodate the adjustable trimmer potentiometer dial.
- Hole 6 : Drill a hole about 1/16″ in diameter to fit the power switch.
Step 5: Placing the Components in the Box
Both banana sockets are at the top of the project window. This step will not require much effort. Simply drill two holes in the top of the box, remove the nut on the end caps and insert. You will then use the clamp nut to secure the device in place. The only exceptions are the NPN transistor and trimmer potentiometer, which you will glue in place.
