// wait for capacitor to charge ~63% (one T = RC)
  while(true) {
    float charge = analogRead(vTestPin)
    elapsedTime= millis() - startTime;
    if(charge > (ADC_RES * .63) {
      microFarads = ((float)elapsedTime / resistorValue) * 1000;
    }
    if(elapsedTime > 2000) {
      microFarads = 0;
    }
  }