DIY Wearable TDCS Device

TDCS (Transcranial Direct Current Stimulation)

In this Instructable, I will:

1. Walk you through the creation of a simple TDCS device.

3. Layout the theory behind the circuits.

2. Introduce some research and explain why a device like this is worth making.

4. Layout some extra information that you can explore and link to valuable resources that helped me make this project, and may help you improve upon what I've made.

NOTE:

READ SAFETY PRECAUTIONS AND RESEARCH BELOW BEFORE USING DEVICE ANYWHERE ON BODY!

Supplies

Mandatory

9v Battery (Amazon)

Transistor (LM334, 2N3906, S8550) - Amazon

Resistors: 470k Ohm, 100 Ohm, 37 Ohm (Amazon)

Electrodes (Many options - see discussion below)

Optional

Switch (Sparkfun, Amazon)

Headband, Skullcap (Amazon)

Battery Clip Connector (Amazon)

Potentiometer/Variable Resistor (Sparkfun, Amazon)

Solder & Soldering Gun

Analog Current Meter (Amazon)

Multimeter

Step 1: Buy/Create Electrodes

Buy

There are many places to buy electrodes for TDCS.

Buyable electrodes come in the following types:

- Self-Adhesive

- Rubber Carbon Electrodes

- Sponge Electrodes

- Amrex Spong Electrodes

- DIY Electrodes

For more information check out the following links:

Create

I created my own electrodes using the following materials:

Caps of Snapple bottles ($1/per)
Paper fasteners
Electrical tape
Household Sponges (cut lengthwise in half, 1/4-inch width)
Water
Salt

Images can be seen above.

Note: To create the bulging effect seen in the sponges, put 1 or 2 sponge pieces in the center of the cap before putting the circular cut piece of sponge inside the cap. Also, bend one of the two prongs of the fasteners onto the cap to hold it in place, and use electrical tape over it to bind the prong to the lid in order to create a good contact.

Connect All Components

Use Circuit Diagram as Guide

All components are laid out along the circuit diagram to aid with the connection.

At the lead ends, connect the leads to the electrode prongs.

When ready to engage the device, turn the switch to on position, and test the electrodes with a multimeter, if possible.

Create Saline Solution for Sponges and Put Sponge Piece Back in Electrode Cap

Read Electrode Placement and Montage Discussion Below

DIY Sponge Directions

1. Combine water and household salt (NaCl) at 2.3 grams per 8 oz of water.

2. Dip sponges into water.

3. Wring enough water out such that sponges don't drip, but they are still wet to the touch (less water is better than too much water for dispersing water through electrode - study)

4. Ensure circuit is disengaged/switched off then put sponges back in caps

Purchased Sponge Directions

1. Salinate sponges or electrodes according to specifications of your respective product.

2. Attach the sponges to the electrode ends.

Discussion

Why TDCS?

TDCS is a form of neuromodulation that uses mild electrical current to produce profound, and quantitative improvements in cognitive and physical tasks. There has been much research done on the subject -- some conclusive, and some less so. I will include numerous research papers that have tested the device and link to other less scientific blogs that include anecdotes of people who have experimented on themselves.

Who uses TDCS?

Experimental neuroscientists, cognitive psychologists, transhumanist fanatics, self-improvement hobbyists, curious tinkerers, and many more.

Is it safe?

There is much research on what's safe and what isn't safe with neurostimulation/neuromodulation. Most research has found that low-current electrical stimulation < 2.5 mA for no more than 30 minutes is safe for the brain and body. Some researchers and enthusiasts have reported minor skin irritation, but if the device is used properly, within the aforementioned current and time range the device is harmless.

What is the Proper Electrode Placement?

Proper electrode placement varies greatly and is determined by the effect that you desire. For example, if you desire to experience "accelerated learning," you should place the positive electrode on your left temple as per the guidelines of research done by DARPA. If instead, you want to improve your mood and help with depression, you should put the cathode at the right supraorbital and the anode at the left DLPFC. For more information on where these locations are, as well as the research that supports them see link. At the bottom of each "montage," you can see the studies related to each electrode placement strategy.