Video & Webpage: https://medium.com/jungletronics/lm741-as-comparator-opamp-e6f308f93eec

_02_basicTronics_LM741_as_amplifier.ino

#include <FlexiTimer2.h>                // use timer for sampling to get even time base for data

const int READ_SINE_PIN = A0;
const int READ_OUTPUT_PIN = A1;


int inverted_value = 0;

void setup() {
  Serial.begin(115200);                 // initialize serial communications (to match that used by PlotNValues.pde)
  
  FlexiTimer2::set(10, sample);
  FlexiTimer2::start();
}

void loop() {
 //wait interruption
}

// sample values and pipe to processing
void sample() {
  String result = "";
  Serial.println(result + analogRead(READ_SINE_PIN) + "," + analogRead(READ_OUTPUT_PIN));
}