I am sending custom code to Arduino with this ardulink command:

{        ArduinoControl.link.sendCustomMessage("oled");

Code from standard Ardulink sketch CustomMessagesChipKit.ino:

  if (stringComplete) {
    if(inputString.startsWith("alp://")) {
    // OK is a message I know (this is general code you can reuse)
      boolean msgRecognized = true;
      if(inputString.substring(6,10) == "cust") { // Custom Message
        // here you can write your own code.
        int separatorPosition = inputString.indexOf('/', 11 );
        int messageIdPosition = inputString.indexOf('?', 11 );
        String customId = inputString.substring(11,separatorPosition);
        String value = inputString.substring(separatorPosition + 1, messageIdPosition);
        if(customId == "oled") {
            //Clear the virtual buffer
            digitalWrite(13, HIGH);
        } else {
          msgRecognized = false;
          // this sketch doesn't know other messages in this case command is ko (not ok)
      } else {
        msgRecognized = false;
        // this sketch doesn't know other messages in this case command is ko (not ok)
      // Prepare reply message if caller supply a message id (this is general code you can reuse)
      int idPosition = inputString.indexOf("?id=");
      if(idPosition != -1) {
        String id = inputString.substring(idPosition + 4);
        // print the reply
        if(msgRecognized) { // this sketch doesn't know other messages in this case command is ko (not ok)
        } else {
        Serial.write(255); // End of Message
    // clear the string:
    inputString = "";
    stringComplete = false;

As a result the LED on pin 13 is turning on after message from java program. But that is all. LCD or or LED on PWM 9 pin are not reacting at all.

Also I could not understand how to send an answer back from Arduino to Ardulink. Can you please show me an example? I would love to send and print data in Java program from DHT11 sensor in response. I know about RawDataListener and I read the whole Ardulink site, but I did not understand that. I a newbie in programming.

When i replace

{String customId = inputString.substring(11,separatorPosition);}


{String customId = inputString.substring(11,15);}

than everything works. What can it be?

2 Answers 2


you can read a complete (real project) example about how to receive messages from Arduino with Ardulink from here: https://github.com/openQCM

In general you can use a listener (digital, analog, and raw) to receive messages from Arduino. A raw listener receive all messages received from Arduino, so you need to implement code to filter the messages you are interested in. Digital and Analog listeners receive events from digital and analog PINs.

The sketch in your question isn't the original sketch you can find in Ardulink distribution. That sketch was written to manage the OLED on the ChipKit shield I have. You have modified the sketch to manage your LCD.

Actually you can send successfully messages from an Ardulink based application (as Ardulink Console) to Arduino since LED on PIN 13 is turned on. So the problem maybe just on your sketch.

To FIX analogWrite on PIN 9 try to set the PIN as OUTPUT with this statement: pinMode(9, OUTPUT);

I cannot help you with lcd library that I don't know.

If you need for some help don't hesitate to write to me.

  • PIN 9 is set as OUTPUT, but it still does not work. I thought it was smth with library too, but i guess it is not. Commented Nov 27, 2015 at 10:35

It looks like you're trying to send a custom message to arduino and have it respond. As a small add on to your code try serialCommand. It pulls in whatever you send over the command line and executes it as a command and returns whatever you need to whatever interface you gave such as softwareSerial.


I offer that you could use the two together to get the results you want.

Let serialCommand listen for commands and execute them and then set up a listener in Java for any serial communication back from the unit.

That's more or less what I end up doing when it comes to bluetooth, rf24, and wifi anyway, so why not serial as well.

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