That is a 1K Ohm Potentiometer. Also called a "variable resistor". But you can go to an electronics store or just google potentiometer and find plenty. You can buy a kit.You could use a resistor there but then you couldn't adjust the gain on the fly as described in the instructable. It's definitely needed.
I'm pretty sure tantalum caps don't have polarity, so you can put it in either way, if that's what you meant.
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I also thought that, I think that is correct (the photoresistor will not be able to output more than 3.3 V since it is connected to 3.3, so I think that solves it)
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I got that code working just by installing the minim package.Sketch->import library->add library-> search minim, installGive it a minute and then should work.
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I have everything set up and working, except it's not quite working.I notice on the Processing program that it does respond to me tapping the electrodes etc., and it gets more erratic when I change the potentiometer value.I am not, however, getting any readable data, and the fluctuations look to be very large and not like the picture shown here; so I'm not sure what's wrong.I've double checked my circuit and all seems to be wired correctly. Like I said, it does get a signal that is coming from the electrodes, but not brain signals.Is it maybe that my hair is in the way? I have electrode gel and everything--not sure what to try/what the problem may be. Any help is much appreciated, thanks!
I think I have figured these out for the most part.I still don't know why tantalums are used--maybe they work differently. I just went through and made sure they were put in correctly according to polarity.I still don't know though (which I didn't ask before) if the 25nF capacitor exists, maybe just me again. I used a 22nF and hopefully that will do the job (no idea, haven't tested it yet)Also, I looked up the datasheets for op amps and learned the basics and then made sure that the different -9V and ground were connected correctly there--still not clear enough for a beginner in this turtorial, but it didn't take much for me to understand the why for the how.
Do I have to use tantalum? From what I can tell tantalum capacitors are polarized, but it's very hard (for me) to figure out which way to put them into the circuit. There's no polarity on the schematic (except for the electrolytics), so did you just use ceramic, or what?
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