GSR Sensor for Grove

GSR is referred to as galvanic skin response, a prominent method in the electronics field used for measuring the electrical conductance of the skin. Basically, Strong emotion can cause a stimulus to your sympathetic nervous system. This results in more sweat being secreted by the sweat glands. Grove – GSR sensor capable of spotting such strong emotions by simply attaching two electrodes to two fingers on one hand. It is quite interesting to create emotion-related projects like sleep quality monitor. And also widely used in some galvanic skin response devices such as lie detectors.

In order to measure GSR, we take advantage of the electrical properties of the skin. Normally the skin resistance varies with respect to sweat gland activity. So the greater sweat gland activity, the more perspiration, and thus, less skin resistance. GSR signal does not measure resistance, but conductance. Conductance is the opposite of resistance and is measured in siemens (Conductance = 1 / Resistance). Thus the conductance makes the signal interpretation easier, since the greater the sweat gland activity, the higher the skin conductance.

By simply applying a constant voltage of usually 0.5 V to the two electrodes that are in contact with the skin, the conductance can be determined. The circuit also contains minimal resistance compared to the skin resistance that is in series with the voltage supplier and the electrodes. As the voltage (V) is kept constant, skin conductance (C) is calculated by measuring the current (I) flow through the electrodes.