Hi everybody,
I would like to record the GSR with Arduino. I know that there are some kits that you can buy and use, but my problem is always the same: I need to control the Arduino from Matlab. All these kits have dedicated libraries and I don't know how to use them in Matlab.
I found a couple of projects to use GSR with Arduino. My doubt is: they look WAAAY to simple, even for me.
They are both fairly similar. Do you think that something like this could work?
I tried it with the only difference that I didn't have a 0.1uF capacitor. Not knowing anything about electronics, I used what I had: a 100 uF capacitor. This is what the result looks like:
Raw Data:
Data converted to Volts (assuming that I did it right):
Data after applying a smoothing technique:
I am not sure whether this makes any sense at all.
Ideas?
P.S.
Bare in mind that I used some random wires that I had. I assume it would be a little bit better if I can get some cables made for electrodes. But still, I don't know whether all this makes sense in the first place.
One more thing: whatever this is doing, it doesn't seem too different from what I would get with something like the BioPac (obviously that's a gazillion times better).
BUT, I have noticed that some things are similar. Like, if I take a deep breath, then the values suddenly increase. Instead, overall the values tend to decrease. Overall, these are two things that I also noticed with other systems.
Also, notice that this is not happening in the pictures that I posted. After posting those I noticed a mistake in the wiring. I rewired the thing and the signal started behaving like I said...
Gluce:
I am not sure whether this makes any sense at all.
Ideas?
As the person doing the experiment, you should have an expectation of what to get out of it.
This is nothing new, so you should first research the method, including the expected response. How else do you even know your method works?
You also should get yourself some nice capacitor kits. Different values, different types. Also understand what a capacitor is, what it does, and what the value means. The 0.1uF used in the experiments you link to is probably a ceramic, maybe a film type, quickly looking at the article didn't tell me which type. Your 100 uF is likely an electrolytic, maybe tantalum. Besides the 1,000 times larger value these caps all have slightly different behaviour and with it use cases, which also may affect your experiment.
Well, I know what the GSR is, I know the physiology behind it, I know how to analyze the data once I have them, but I don't know technically how to create a device that records it. That's not my field.
I'm a psychologist. Usually, we have something like the BioPac to record it. All you have to do is knowing the program (AcqKnowledge, in case of the biopac), and start recording.
But I am working in a new University and they don't have anything to record the GSR and they don't have 8000+ dollars to buy the BioPac.
So...I am trying to get something cheap that is not too bad. However, the circuit that I made, I am not 100% sure that is actually recording the conductivity of the skin. It looks like it is, but this circuit looks just too simple and cheap. I mean, there must be a reason why the biopac costs so much (even though the price is way overpriced).
But also, if you look at the GSR kit sold by adafruit, they too have a circuit that is more complex than what I made.
As for the capacitor, I will buy the same as in the article that I posted. I read a little bit about capacitors, but then again, it is kind of hard to make an informed choice if you have no literacy about electronics. I would not know where to start.
