Well done on step by step debugging such as double checking the wiring on the electronics side and testing the blink code with the Arduino alone to isolate the issue.
If the Blink sketch is the only Arduino code you have uploaded to your board that won't suffice. Processing does send messages to Arduino (which is why you see the RX LED turn on), but there's nothing in the Arduino code that initialises Serial communication
As you can see in that example, in setup() Serial communication is initialised with 9600 baud rate (communication speed, 9600 bytes/chars per second):
Serial.begin(9600);
Then in draw() if there is data available, each character is read, then printed one at a time with a prefixed message:
// send data only when you receive data:
if (Serial.available() > 0) {
// read the incoming byte:
incomingByte = Serial.read();
// say what you got:
Serial.print("I received: ");
Serial.println(incomingByte, DEC);
}
If you upload the example linked, if you've got a single Serial port, you should see both the RX then ever so slightly after the TX LED blinking when you run your Processing sketch. If you close that sketch, open Serial Monitor in Arduino and type something then press enter you'll see the debugging message read back from Arduino.
Using these notions you could write a basic sketch like so:
int incomingByte = 0; // for incoming serial data
void setup() {
pinMode(9, OUTPUT);
Serial.begin(9600);
}
void loop() {
// send data only when you receive data:
if (Serial.available() > 0) {
// read the incoming byte:
incomingByte = Serial.read();
// say what you got:
Serial.print("I received: ");
Serial.println(incomingByte, DEC);
// if we received ASCII character '1', turn LED on
if(incomingByte == '1'){
digitalWrite(9,HIGH);
}
// if we received ASCII character '0', turn LED off
if(incomingByte == '0'){
digitalWrite(9,LOW);
}
}
}
Uploading this sketch to your Arduino should allow you to type 1 into Serial Monitor and press Enter to turn the LED on or 0 to turn it off.
The only thing left is to send the same data from Processing:
import processing.serial.*;
Serial arduino;
void setup(){
try{
arduino = new Serial(this, Serial.list()[0], 9600);
}catch(Exception e){
println("error connecting to serial port, double chek USB connection, serial port and close other programs using Serial");
e.printStackTrace();
}
}
void draw(){
}
void keyPressed(){
if(key == '1'){
if(arduino != null){
arduino.write('1');
}else{
println("arduino serial connection wasn't initialised");
}
background(255);
}
if(key == '0'){
if(arduino != null){
arduino.write('0');
}else{
println("arduino serial connection wasn't initialised");
}
background(0);
}
}
Minor side note: notice I'm not using delay() in Processing, I recommend using millis() instead as it doesn't block the execution of code like delay() does.
So the above looks like quite a bit of code just to blink an LED but the point is to understand the basics of Serial communication which will be useful on the long run:
- initialising serial communication with Arduino (understand baud rate)
- basic reading/writing of bytes over Serial
- initialising serial communication from Processing and sending data
Back to your original question, you've missed an important detail regarding the Arduino library you're using in Processing: it's relying on a special Arduino sketch (firmware) called Firmata. You will be able to read more on that and how to use the library in this Arduino and Processing tutorial.
As the tutorial mentions you need to first upload this sketch from Arduino > Examples > Firmata > StandardFirmata. Also bare in mind baud rate is set to 57600, not 9600 so you need to update your code like so:
arduino = new Arduino(this, Arduino.list()[0], 57600);
