Making the Galvanic Skin Response / by Sebastian Morales

This sensor is based on the one described on Make magazine by Sean Montgomery. The following pictures are taken from there. 

I was looking to spend about $0 in this circuit so wanted to use only components found on the ITP shop. The circuit diagram calls for a MCP6002 Op-Amp but I could only find the IM358 in stock. I also didn't find the resistors so I combined my own. 

I also added a k-pot to control the threshold of the sensor.  In the picture the LED is disconected form the circuit, insetead i connected a wire into the an arduino to later plot the values.