PComp Lab: Serial Output From P5.js

In this lab we are using P5 to control Arduino serially.
We start by programming our board to change LED brightness
if you press “H” for high or “L”for low.  It looks like this, in Arduino code:.
constintledPin = 5; // the pin that the LED is attached to
int incomingByte;     // a variable to read incoming serial data into
void setup() {
 Serial.begin(9600);             // initialize serial communication
 pinMode(ledPin, OUTPUT);        // initialize the LED pin as an output
void loop() {
 if (Serial.available() > 0) {   // see if there's incoming serial data
   incomingByte = Serial.read(); // read it
   if (incomingByte == 'H') {    // if it's a capital H (ASCII 72),
     digitalWrite(ledPin, HIGH); // turn on the LED
   if (incomingByte == 'L') {    // if it's an L (ASCII 76)
     digitalWrite(ledPin, LOW);  // turn off the LED
In P5.js, We can use H and L to control the intensity of the LED by writing
function keyPressed() {
 if (key ==='H' || key ==='L') { // if the user presses H or L
 serial.write(key);              // send it out the serial port
Here’s the result:

Categories: itp, lab, pcomp

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