Analog input goes to processing graph.

analog input to serial

const int SENSOR = A0;
const int LED = 13;

int val = 0;
int max = 0;

void setup() {
  Serial.begin(9600);
  pinMode(SENSOR, INPUT);
  pinMode(LED, OUTPUT);
}

void loop() {
  val = analogRead(SENSOR);

  if (val > max) {
    max = val;
  }
  
  String space = " ";

  Serial.println(val);

  if (val > 1) {
    digitalWrite(LED, HIGH);
  } else {
    digitalWrite(LED, LOW);
  }
  
  delay(10);

}

serial input to graph

import processing.serial.*;

Serial myPort;

int xPos = 1;
float max = 0;
float cur = 0;

void setup() {
  size(720, 240);
  println(Serial.list());
  myPort = new Serial(this, Serial.list()[2], 9600);
  myPort.bufferUntil('\n');
  background(58,179,254);
}

void draw() {
}

void serialEvent(Serial myPort) {
  String inString = myPort.readStringUntil('\n');
  if (inString != null) {
    inString = trim(inString);
    float inByte = float(inString);
    inByte = map(inByte, 0, 50, 0, height);
    
    stroke(13,0,192);
    line(xPos, height, xPos, height - inByte);
    
    if (xPos >= width) {
      xPos = 0;
      max = 0;
      background(58,179,254);
    } else {
      xPos++;
    }
    
    if (inByte > max) {
      stroke(58,179,254);
      line(0, height - max, width, height - max);
      max = inByte;
      cur = height - inByte;
      stroke(13,0,192);
      line(0, cur, width, cur);
    } 
  }
}