Galvanic Skin Response output display/electrode

[shamog]

Hi... I'm building a GSR unit for a school proj. I've managed to find working circuits of such devices. However I would like the output to be displayed either in analog/digital format or perhaps link it up to a pc if its possible... Is there any common circuitry that i can use for the output and calibrate it?

I'm also unsure of what to use as electrodes for the device. I've attached a schematics of the device. Any suggestions would greatly help. Many thanks!


PS. Would it be possible to substitute opa1013d?

 

[Klaus]

The GSR meters we have here have analog meters to read the output. These are of the + - scale variety ( the needle is at mid scale at rest), I guess it has a micro Amp movement ( never checked this out) - its quite sensitive.
Our meters also have an audible feedback output, useful if you want to use the GSR for relaxation.
What you also need is a 'range' switch as the skin resistance can vary over a great range and without such a switch the meter would most likely be pinned at one end or other of the scale.
You also need a sensitivity adjustment. These controls could be a corse and fine adjustment of the op amp gain.

Computer output is possible but perhaps a little complex to start out with.

Regarding electrodes, if you use it on the fingers then small, soft stainless steel wool pads attached to velcro strips work well. The ones we have are attached with a small eyelet which also has the wire soldered to it.

 

[shamog]

Galvanic Skin Response Output Alternatives

Hi guys,

I've managed to build a circuit contributed by a Mr. Ravi sometime last year. Its working fairly well except that the LED output seems a little unstable. This, he says, is due to the electrode. He suggested using silver electrodes attached to shielded cables for better results.

I would like to know if instead of having 2 separate source - 1.5V and 9V -whether it would be possible to run on a single integrated supply. If not, what's the reason behind it.

Also, instead of using the output signal to drive the led, channel it to a computer. I know there has to be some type of ADC involve. Could anyone point me to any website that has step by step guide.

Even after conversion there has to be some form of interfacing involve rite? What are the common types of program used? is there any free available template that can be modified for use? I have some knowledge in C programming but none at all in electronic.

Please advise. Thanks!

Happy Holidays!
shamog