I recently reviewed the tDCS-Kit.com devices and found them to be useful but “bare-bones”. For about $40 you get a current regulated tDCS device that puts out a max of about 2 mA. ( See https://speakwisdom.wordpress.com/2013/11/03/product-review-tdcs-kit-com-tdcs-devices/ ) While I’m not a fan of the USB version, the 9-volt battery version deserves consideration. Being “bare-bones”, the device is a bit harsh on start-up and shutdown and offers no control of the current delivered other than the 2 mA limit.
I constantly receive emails and messages from folks from all over the world complaining that they cannot afford the $250 (or more) the more sophisticated tDCS devices cost. Yet they are desperate for help with depression, chronic pain, etc. So the price of the tDCS-kit.com device is attractive – it provides a serviceable tDCS device at a very low cost.
With a very simple modification, the tDCS-kit.com device can have current control! That means you can start and end a tDCS session by ramping current up and down in a comfortable way – and limiting current at a desired level (say 1 or 1.5 mA.)
Here is what you need:
1. 5 k-Ohm linear potentiometer RS part 271-1714 $3.49
1. Project box RS part 270-1801 $3.49
1. Knob from your junk box or other source
You also need the ability (or have a friend) who can do some basic soldering.
Simply put, the potentiometer will be connected ACROSS the anode and cathode lead from the tDCS-kit.com device. It will act as an adjustable alternate pathway for current so that not all of the 2 mA from the tDCS device will pass through your head. Along the way, you may want to replace the “pin” style connectors with alligator clips (my preference) or banana plugs.
(I put the potentiometer in a little project box. Note that I clipped the pin connectors off and soldered the red-striped lead to the center of the potentiometer. The red anode lead to the electrode also goes there. The black cathode leads are soldered to the bottom terminal of the potentiometer.)
(Complete! tDCS-Kit module is at the left. Leads to electrodes appear at the right.)
May I suggest you also spend a little money and buy a digital multi-meter (many for $10 or less.) You will need that to monitor the current level you are using for your tDCS session. The multi-meter is set to read current and is placed in series with the red (anode) lead and connects to that electrode. With the modification shown above, you can vary current up to the max of 2 mA that the device will deliver.
Warning: Disconnect the battery when not using the device as there will always be a load present.
I think you will find this simple modification makes the tDCS-Kit.com device far more versatile and comfortable to use.
As with any DIY tDCS project, you are responsible for your own actions and safety. If you are not sure what you are doing STOP and get help from a professional and/or read, read, read about tDCS.