okay so after so much searching around i finally designed my first stage of my brain-computer interface, this isn’t something really special, but here’s how it will work:

• this is just an input buffer, which will take in biosignals from the brain which are high impedance and you cant do any filtering stuff with it cuz it will distort the signal, and it will convert them into low impedance
• the non inverting input also sits are half of vcc, therefore the output will also sit at half, this is useful as op amps are usually supplies power like +9 and -9 but since we will power this from a microcontroller it will only have a single supply power, if we just it hooked up without dividing voltage the negative signals will be lost so we make a virtual gnd , so we can see positive and neg signals with ADC