One of the accepted treatments for hyperhidrosis (excessive sweating) is iontophoresis. Iontophoresis involves running a small current through the hands, feet, or armpits of the patient. Some people set the current whereas others set the voltage for a session. I wanted to see if these control methods were equivalent. Safety concerns around the body and electricity are obviously very important and complicated. RA Fischer, a manufacturer of an FDA approved device, has max settings of 30mA and 58V. To be on the safe side, I chose to use only 9V in my tests.

Start up screen. Session screen.

Start up and sessions screens.

I used a raspberry pi, a bundled voltage/current sensor, and a 9V battery. I added a 16x2 LCD display that shows relevant session information and allows adjustment of starting values by pushbutton. As a learning exercise, I used C to write most of the code. However, to interface with the current/voltage sensor I embedded python code in the C code.

To test the device, I placed my hands in the two plastic containers with aluminum foil electrodes covered by paper towels and just enough tap water to cover my palms. (I also added a ¼ teaspoon each of salt and backing soda as our water has a low mineral content.)

Breadboard with potentiometers. Breadboard with screen and buttons.

Close up showing the breadboard wiring.

Setup of the testing circuit and iontophoresis device. Shows two 9V batteries, however, in the end only one was used.

Setup of the iontophoresis device.

Despite having a fairly constant voltage at about 8.5V, the current present in the circuit varied from 2mA-4.5mA through the 10-minute session. Clearly a constant voltage does not equate to a constant current. What remains unclear is whether controlling the voltage, the current, or some other parameter such as total charge (i.e. current×time) works best.

Graph of the voltage during the session. Graph of the current during the session. Graph of the resistance during the session. Graph of the power during the session.

Data collected during the session.