Galvanic Skin Response Sensor
Galvanic Skin Response GSR or Electrodermal Activity is the study of the change in human skin conductivity (resistance) under different psychological conditions. Used in lie detectors (polygraph) and biofeedback devices, the measurement is actually quite simple but frequently associated with expensive equipment. I present a number of inexpensive alternatives for measuring skin resistance openly available for researchers and hobbyists.
Over the last 15 years I’ve had many webpages dedicated to building homebrew LEGO sensors. The one that always got the most hits was the one on Galvanic Skin Response or GSR. I’ve fielded many emails for more information about GSR and how to build the sensor with something other than the LEGO Mindstorms kit. I wonder how many sets LEGO sold to people only interested in using it to measure GSR. It seemed to me that I should provide another more relevant way to homebrew a GSR sensor using a smartphone.