// line plotter using constant minimum and maximum values to keep graph from resizing

const int aMIN =  -23;
const int aMAX = 1023;
const int graphoffset = 1000;

unsigned long dTimer, dTimeout = 500, timer, timeout = 7000;

void setup() {
  Serial.begin(1115200);
  pinMode(LED_BUILTIN, OUTPUT);
}

void loop() {
  int a0r = analogRead(A0), a1r = analogRead(A1);
  byte d13r = digitalRead(LED_BUILTIN);
  Serial.print(aMIN); // minimum value data point to plot
  Serial.print(","); // separator between data points
  Serial.print(a0r); // floating value data point
  Serial.print(",");
  Serial.print(a1r);
  Serial.print(",");
  Serial.print(d13r * graphoffset); // plot LED_BUILTIN value
  Serial.print(",");
  Serial.print(aMAX); // maximum value data point to plot
  Serial.println(); // CR/LF sends this set of data points to line plotter

  if (millis() - dTimer > dTimeout) { // compare "now" to timeout variable
    dTimer = millis(); // reset timer
    digitalWrite(LED_BUILTIN, !digitalRead(LED_BUILTIN)); // invert digital reading
  }
}