[Help] - EEG Arduino Circuit

[Giorgos_xou]

Hello people,

I was having some trouble lately these days, recreating and testing an EEG circuit from chipstein's page.The problem is that it doesn't work and can't find a way to make it work so i decided to ask you guys for help.

First of all for an unknown reason one of my recreated boards, had some weird Analog Output values, that when i was touching the floating ground, something like a capacitor was discharging, was happening each time, making the values go from 0 to 255 again and again..., making me think, that something was going on with the parts. So, i made another one again, with new parts and most of them tested afterwards (except the chips), but in the end it didnt work at all, it had all the time an output of "255" even if i was touching the floating ground.

In conclusion i had to recheck the board "hundrends of times" that many times that i ve even memorized it, lol.If anyone could give me any suggestions or check the circuit and let me know about his/her thoughts, i would love to hear and i would be really thankfull for it.

Thanks in advance for any help,
George.

#define ANALOG_IN 0


void setup() {

  Serial.begin(9600);
  analogReference(INTERNAL);

}


void loop() {

  int val = analogRead(ANALOG_IN);

 Serial.print( (val >> 8) & 0xff);
 Serial.print(" - ");
 Serial.print( val & 0xff);
 Serial.print(" \n");
 
}

Part's Datasheets:
AD620
CA3130

Helpfull Links:
Basic Schematic Question: Op amps
DIY EEG's

[Giorgos_xou]

i am really sorry for that , i was in hurry but even then i think that it has what it needs in order to be undestood +i have no good knowledge on amplifiers and circuits like this, making me less capable of giving many information about the subject.

it doesnt give any errors as i dont mention and it is something i forgot and i am sorry

i was excpecting to have a range of output values bettween 0-255 when i was consentrated or let my mind relax

and not a different range when i was toching the floating ground (at the first try ...) or an output of 255 all the time (second try where i tested most of the parts), as i mentioned here

Something like a capacitor was discharging, was happening each time, making the values go from 0 to 255 again and again..., making me think, that something was going on with the parts. So, i made another one again, with new parts and most of them tested afterwards (except the chips), but in the end it didnt work at all, it had all the time an output of "255" even if i was touching the floating ground.

.

Thanks for your reply even if i think that it is a little bit harsh in a way unless it is in a satirical way... (: