From my understanding, the GSR sensor is actually measuring the change in skin resistance and outputting this as a voltage level (0-5V for Arduino Uno) and is not directly measuring the skin conductance (this would require a constant voltage and a measurement of current between the electrodes which the ADC on the Arduino does not measure). Thus, with greater levels of human arousal, the resistance will decrease and therefore voltage should increase. However, from looking at the output graphs on the wiki page it seems that voltage is proportional to the resistance - it decreases with greater arousal which goes against my initial thoughts of voltage being inversely proportional to resistance.
Therefore, please could someone clarify what the output of the GSR actually represents and the what the sensing circuit is measuring (e.g. resistance or conductance) and how it is achieving this. Your feedback on this matter will be much appreciated. Thanks.
I have viewed the wiki page for the GSR sensor many times but it does not answer my question. The graphs shown on the wiki page show that the voltage (ADC conversion by the arduino) DECREASES as the user appears to be aroused/stressed. However skin conductance INCREASES when the user is aroused/stressed therefore the voltage shown in the arduino output seems to be proportional to the skin RESISTANCE and not the skin conductance. Skin Conductance = 1 / Skin Resistance.
How it is possible to get a reading of Skin Conductance in micro siemens (normal unit of skin conductance) from the voltage output of the arduino?
Please could you let me know the material used for the electrodes that make contact with the skin
Hi both,
I have the same question and am wondering what exactly do the values represent (sometimes in the range of 150 -200 and sometimes over 300). Are these conductance values in microsiemens?
I would really appreciate a reply
I have doubt too and can’t find the answer about GSR output units. I got output values from 300 to 800…and can’t derive any conclusion…
Please, have anybody find the answer? What are those units and how can I interpret them?
