import processing.serial.*;
Serial myPort;
int lf = 10;

void setup(){
  size(300,300);
  //fill(0,255,0);
  //ellipse(100,100,100,100);
  //myPort = new Serial(this,"/dev/cu.usbmodem1421",9600);
  myPort = new Serial(this,"/dev/tty.usbserial",9600);
}

void draw(){
  while(myPort.available() > 0){
    String str = myPort.readStringUntil(lf);
    //println(str);
    if(str!=null){
      int value = Integer.parseInt(trim(str));
      int nValue = (value-200)*4;
      println(nValue);
      background(nValue);
    }

  }
}

#include "SoftwareSerial.h"

const int analogInPin =  A2;  // Analog input pin that the potentiometer is attached to
int sensorValue = 0;        // value read from the pot
int outputValue = 0;        // value output to the PWM (analog out)

const int Rx = 1; // this is physical pin 7
const int Tx = 2; // this is physical pin 6
SoftwareSerial mySerial(Rx, Tx);

void setup() {
//  pinMode(3, OUTPUT);
  pinMode(Rx, INPUT);
  pinMode(Tx, OUTPUT);
  mySerial.begin(9600); // send serial data at 9600 bits/sec
}

void loop() {
  // read the analog in value:
  sensorValue = analogRead(analogInPin);
  // map it to the range of the analog out:
  outputValue = map(sensorValue, 0, 1023, 0, 255);
  mySerial.println(outputValue);
  delay(100);

}