Assignment 9 – Serial Communication

Exercise 1.

p5 code:

let position;
let mass = 50;
let potValue = 0; 


function setup() {
  createCanvas(640, 360);
  noFill();

  // Initialize position of the ellipse
  position = createVector(width / 2, height / 2);

}

function draw() {
  background(255);

  // Map potentiometer value to horizontal position
  position.x = map(potValue, 0, 1023, 0, width);

  // Keep the ellipse in the middle 
  ellipse(position.x, height / 2, mass, mass);
}

function keyPressed(){
   if (key == " ") { //set up serial
     setUpSerial();
   } 
}

function readSerial(value) {
  potValue = int(value); // Parse the potentiometer value
}

Arduino Code:

void setup() {
  Serial.begin(9600); // Start serial communication 
}

void loop() {
  int potValue = analogRead(A0); // Read the potentiometer value 
  Serial.println(potValue);     // Send the value to p5.js
  delay(10);                    
}

Exercise 2.

p5 code:

function setup() {
  createCanvas(400, 400);
}

function draw() {
  background(225);

  // brightness based on cursor's x position
  let brightness = map(mouseX, 0, width, 0, 255);
  brightness = constrain(brightness, 0, 255); // Ensure brightness stays within range

  // Send brightness value to Arduino if serial is active
  if (serialActive) {
    writeSerial(`${brightness}\n`); 
  }
}

function keyPressed(){
   if (key == " ") { //set up serial
     setUpSerial();
   } 
}

function readSerial(value) {
  potValue = int(value); // Parse the potentiometer value
}

Arduino Code:

int ledPin = 9; 
int brightness = 0; 

void setup() {
  Serial.begin(9600); // Start serial communication
  pinMode(ledPin, OUTPUT); //LED pin as output
}

void loop() {
  if (Serial.available() > 0) {
    // Read the incoming brightness value
    brightness = Serial.parseInt();
    brightness = constrain(brightness, 0, 255);

    // Set the LED brightness
    analogWrite(ledPin, brightness);
  }
}

Exercise 3.

p5 code:

let velocity;
let gravity;
let position;
let acceleration;
let wind;
let drag = 0.99;
let mass = 50;
let potValue = 0; // potentiometer value
let serialConnected = false; 
let onGround = false; // whether ball is on the ground

function setup() {
  createCanvas(640, 360);
  noFill();
  position = createVector(width / 2, 0);
  velocity = createVector(0, 0);
  acceleration = createVector(0, 0);
  gravity = createVector(0, 0.5 * mass);
  wind = createVector(0, 0);
}

function draw() {
  background(255);
  if (!serialConnected) {
    textAlign(CENTER, CENTER);
    fill(0);
    text("Press 'Space' key on the keyboard", width / 2, height / 2);
    return;
  }

  applyForce(wind);
  applyForce(gravity);
  velocity.add(acceleration);
  velocity.mult(drag);
  position.add(velocity);
  acceleration.mult(0);
  
// check for bounce on the x axis
  if (position.x > width - mass / 2) {
    if(!onGround){
    position.x = width - mass / 2; 
    velocity.x *= -0.9;
    }
  }
    else if (position.x < mass / 2) {
      position.x = mass / 2; 
    velocity.x *= -0.9;
    }
  
  // check for bounce on the y axis
if (position.y > height - mass / 2) {
  velocity.y *= -0.9; 
  position.y = height - mass / 2; 
  if (!onGround) {
    sendBounceSignal(); 
    onGround = true; 
  }
} else {
  onGround = false; 
}

  wind.x = map(potValue, 0, 1023, -1, 1); 
  ellipse(position.x, position.y, mass, mass);

  // boundaries on x axis
  if (position.x > width - mass / 2 || position.x < mass / 2) {
    velocity.x *= -0.9; 
  }
}

function applyForce(force) {
  let f = p5.Vector.div(force, mass);
  acceleration.add(f);
}

// bouncing signal to Arduino
function sendBounceSignal() {
  if (serialActive) {
    let sendToArduino = "1\n"; 
    writeSerial(sendToArduino);
  }
}

// receive data from Arduino
function readSerial(data) {
    potValue = int(trim(data)); 
}

// initialize serial connection
function keyPressed() {
  if (key == ' ') {
    mass = random(10,100);
    setUpSerial(); 
    serialConnected = true; 
  }
}

function serialOpened() {
  serialActive = true; 
}

Arduino code:

const int potPin = A0; 
const int ledPin = 13; 
int potValue = 0; 
bool ledState;     

void setup() {
  pinMode(ledPin, OUTPUT);
  Serial.begin(9600);
}

void loop() {
  // read the potentiometer value
  potValue = analogRead(potPin);

  // send potentiometer value to p5
  Serial.println(potValue);

  // check for data from p5
  if (Serial.available() > 0) {
    char received = Serial.read(); 

    if (received == '1' && !ledState) {
      // turn on the LED 
      digitalWrite(ledPin, HIGH);
      ledState = true;
      delay(100); 
      // turn off the LED
      digitalWrite(ledPin, LOW);  
    }
    else if (received != '1'){
      ledState = false;
    }
  }
  delay(50); 
}

Video demonstration: