How to make an input from computer using processing (like a password form) and trigger pin in arduino? If you let some link to read more that would be very helpful.

  • 4
    What part are you having problems with? Sending data to Arduino from Processing or parsing data on the Arduino? Your question is very vague. Read up on arduino.cc/en/reference/serial
    – sachleen
    May 3, 2014 at 20:55
  • 2
    What exactly are you trying to accomplish in your project? Please be more specific.
    – Paul
    May 3, 2014 at 22:29
  • I want to enter a pass through processing and if its correct i want to trigger a pin.
    – TanJay
    May 4, 2014 at 4:08
  • Should it be the PC or the arduino which checks the password? What happens if someone uses their own pc program instead of yours? May 4, 2014 at 4:38
  • Arduino should have to contain the password
    – TanJay
    May 4, 2014 at 4:42

2 Answers 2


On the processing side you need to communicate with the arduino using the Serial class. To set up use something like the following. It is a bit of guess work to find which of the serial ports to use

Serial myPort;  
void setup() {
  // List all the available serial ports:

  // Open the port you are using at the rate you want:
  myPort = new Serial(this, Serial.list()[6], 9600);
  myPort.buffer(2); // sets the size of the buffer, I send two bytes at a time

You can read a write using the Serial.read() and Serial.write() see https://processing.org/reference/libraries/serial/index.html for the processing serial references.


You need to have a look at the Serial commands: http://arduino.cc/en/Serial/read


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