Multiple Values from Processing to Arduino through Serial Port

Processing Electronics (Arduino, etc.)
2

Hi Cai,

It can be quite tricky to communicate with an arduino. I spent 2 days figuring out how to do it for my project: A universal ambilight

I adapted the basic Serial example form processing. The idea stays the same: when the mouse is over the rectangle then then an LED connected to the pin number 4 light up.

The processing code:

import processing.serial.*;

Serial myPort;

void setup() 
{
  size(300, 300);
  myPort = new Serial(this, Serial.list()[0], 9600);
  delay(5000);
}

void draw() {
  background(20);
  
  myPort.write(mouseX + ";" + mouseY + ";");

  if (mouseOverRect()) {
    fill(220, 20, 20);
  } else {
    fill(200);
  }
  rect(100, 100, 100, 100);
}

boolean mouseOverRect() { // Test if mouse is over square
  return ((mouseX >= 100) && (mouseX <= 200) && (mouseY >= 100) && (mouseY <= 200));
}

The arduino code:

const long BAUD_RATE = 9600;
int x, y;

void setup() {
  Serial.begin(BAUD_RATE);
  pinMode(4, OUTPUT);
  digitalWrite(4, LOW);
  pinMode(13, OUTPUT);
  digitalWrite(13, LOW);
  newData = false;
  x = 0;
  y = 0;
}

void loop() {
  receiveData();
  
  if (x >= 100 && x <= 200 && y >= 100 && y <= 200) {
    digitalWrite(4, HIGH);
  } else {
    digitalWrite(4, LOW);
  }
}

void receiveData() {
  if (Serial.available() > 0) {
    x = Serial.parseInt();
    y = Serial.parseInt();
    Serial.read();
  }
}

Two things are worth noticing:

  • The delay(5000) is used to let the time to the arduino mode to correctly make the connection with the computer.
  • Be careful at the baud rate, it can be the reason why you can’t read some data. In my project, I had to set the baud rate to 500000 to make it works.
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