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Topic: Galvanic Skin Response Board. (Read 2966 times) previous topic - next topic

Leakster

Hi, I'm very much a newcomer to Arduino and electronics in general so apologies if I seem a bit wet behind the ears.

Basically my problem is I need to create a board that will measure the electrical resistance in a subjects skin and then output the results via bluetooth.

Does anyone know of any projects of a similar nature that they can point me towards to aid me in my research? Any help would be much appreciated, I'm a bit lost in this world of resistors and a little friendly guidance would really help me out.

Grumpy_Mike

#1
Nov 15, 2010, 04:15 pm Last Edit: Nov 15, 2010, 04:23 pm by Grumpy_Mike Reason: 1
Quote
measure the electrical resistance in a subjects skin


Odd choice of words. Normally the resistance is between the skin and the electrode you are measuring, the actual skin's resistance is masked by all the other body stuff inside the skin.

Basically you need to supply more information about what you are trying to do. Are you trying to make some sort of lie detector?

see this:-
http://www.chris3000.com/archive/galvanic-skin-response/

Leakster

I phrased it quite poorly, I apologise. The link is helpful, thanks :)
The ultimate aim of the project is to combine it with a heart rate monitor to be able to monitor a subjects emotions and stress level.

robtillaart

Quote
The ultimate aim of the project is to combine it with a heart rate monitor to be able to monitor a subjects emotions and stress level.

Medical or gaming industry or ...? Reason of this question is that the medical industry has far more rules to apply to.
Rob Tillaart

Nederlandse sectie - http://arduino.cc/forum/index.php/board,77.0.html -
(Please do not PM for private consultancy)

Leon Heller

#4
Nov 15, 2010, 07:56 pm Last Edit: Nov 15, 2010, 08:00 pm by leon_heller Reason: 1
Both need a lot of attention paid to electrical safety. It doesn't sound as if the OP has the experience needed to design this sort of equipment; plenty of insurance cover would be advisable if he wires anyone else up to his contraption.
Leon Heller
G1HSM

Leakster

It's for a study into mobile learning, hence the need for it to be bluetooth, so the subject is freely able to move.
Final circuit design and build will be looked over by an electrician and the Heart Rate Monitor is off the shelf equipment that's already available.
I was just hoping someone might give me some guidance and direction with my research as there's a lot out there and it can be a bit daunting.
Thanks though.

Grumpy_Mike

I would advise you to use AC rather than DC as the DC tends to corrode the probes due to electrolysis. Use one of the PWM outputs as a source and use a series capacitor, rectifier and smoothing capacitor going into the analogue input of the arduino. Also use gold plated electrodes.

pwillard

#7
Nov 18, 2010, 05:26 pm Last Edit: Nov 18, 2010, 05:28 pm by pwillard Reason: 1
There are some off-the-shelf Instrumentation Amplifiers that would simplify your input circuit and would work rail-to-rail making it well suited to using the built-in A/D input of the arduino.  Analog Devices has specialized in medical grade devices for many years.  At about $7.00 the AD8220 is kind of pricey but it would be a good choice.

I'm not sure that the LM324 is considered to be best choice here, that's why I mention it.


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