I've tried to run a serial communication between my arduino and java as per the instructions here:
Arduino Playground - Java, but every time I run the program I get the output "Could not find COM port."
I verified that my arduino is on COM3, and that the program is looking for COM 3, but still no luck. I'm on windows 7 64 bit, if it matters.
Without seeing your code it is hard to say.
It should be pretty much identical to the code in the example.
Here's my arduino code:
void setup(){
Serial.begin(9600);
}
void loop(){
Serial.println("Hellow world");
delay(1000);
}
and here's my java code:
/*
* To change this template, choose Tools | Templates
* and open the template in the editor.
*/
package serialtest;
import java.io.BufferedReader;
import java.io.InputStreamReader;
import java.io.OutputStream;
import gnu.io.CommPortIdentifier;
import gnu.io.SerialPort;
import gnu.io.SerialPortEvent;
import gnu.io.SerialPortEventListener;
import java.util.Enumeration;
public class SerialTest implements SerialPortEventListener {
SerialPort serialPort;
/** The port we're normally going to use. */
private static final String PORT_NAMES[] = {
"/dev/tty.usbserial-A9007UX1", // Mac OS X
"/dev/ttyACM0", // Raspberry Pi
"/dev/ttyUSB0", // Linux
"COM3", // Windows
};
/**
* A BufferedReader which will be fed by a InputStreamReader
* converting the bytes into characters
* making the displayed results codepage independent
*/
private BufferedReader input;
/** The output stream to the port */
private OutputStream output;
/** Milliseconds to block while waiting for port open */
private static final int TIME_OUT = 2000;
/** Default bits per second for COM port. */
private static final int DATA_RATE = 9600;
public void initialize() {
// the next line is for Raspberry Pi and
// gets us into the while loop and was suggested here was suggested http://www.raspberrypi.org/phpBB3/viewtopic.php?f=81&t=32186
System.setProperty("gnu.io.rxtx.SerialPorts", "/dev/ttyACM0");
CommPortIdentifier portId = null;
Enumeration portEnum = CommPortIdentifier.getPortIdentifiers();
//First, Find an instance of serial port as set in PORT_NAMES.
while (portEnum.hasMoreElements()) {
CommPortIdentifier currPortId = (CommPortIdentifier) portEnum.nextElement();
for (String portName : PORT_NAMES) {
if (currPortId.getName().equals(portName)) {
portId = currPortId;
break;
}
}
}
if (portId == null) {
System.out.println("Could not find COM port.");
return;
}
try {
// open serial port, and use class name for the appName.
serialPort = (SerialPort) portId.open(this.getClass().getName(),
TIME_OUT);
// set port parameters
serialPort.setSerialPortParams(DATA_RATE,
SerialPort.DATABITS_8,
SerialPort.STOPBITS_1,
SerialPort.PARITY_NONE);
// open the streams
input = new BufferedReader(new InputStreamReader(serialPort.getInputStream()));
output = serialPort.getOutputStream();
// add event listeners
serialPort.addEventListener(this);
serialPort.notifyOnDataAvailable(true);
} catch (Exception e) {
System.err.println(e.toString());
}
}
/**
* This should be called when you stop using the port.
* This will prevent port locking on platforms like Linux.
*/
public synchronized void close() {
if (serialPort != null) {
serialPort.removeEventListener();
serialPort.close();
}
}
/**
* Handle an event on the serial port. Read the data and print it.
*/
public synchronized void serialEvent(SerialPortEvent oEvent) {
if (oEvent.getEventType() == SerialPortEvent.DATA_AVAILABLE) {
try {
String inputLine=input.readLine();
System.out.println(inputLine);
} catch (Exception e) {
System.err.println(e.toString());
}
}
// Ignore all the other eventTypes, but you should consider the other ones.
}
public static void main(String[] args) throws Exception {
SerialTest main = new SerialTest();
main.initialize();
Thread t=new Thread() {
public void run() {
//the following line will keep this app alive for 1000 seconds,
//waiting for events to occur and responding to them (printing incoming messages to console).
try {Thread.sleep(1000000);} catch (InterruptedException ie) {}
}
};
t.start();
System.out.println("Started");
}
}
Thanks.
The code looks fine to me.
I assume you haven't got the Arduino's serial monitor open have you?
Can you get Java to print out all the ports it can see?
I haven't had any luck getting it to print the ports it can see. Adding a System.out.println line to this program just prints null, haven't gotten anything else I could find on the web to work because of troubles with javax.comm and I don't have the serial monitor open
In Processing which is a flavor of java I use:-
println(Serial.list());
To get a list of serial ports.
Could you not change this code:-
for (String portName : PORT_NAMES) {
if (currPortId.getName().equals(portName)) {
portId = currPortId;
break;
}
}
To print out each name as you test for it?
I tried that, and dind't get anything to print at all (?) , hovever, in the mean time I managed to get it to work by commenting out the line of code "System.setProperty("gnu.io.rxtx.SerialPorts", "/dev/ttyACM0");" Thanks for your help though!
Which Arduino do you use? A real Arduino or a clone? There are several clones that not support serial communication as Arduino.
However if you want test communication I suggest you to upload a simple sketch with serial in/out commands from Arduino IDE examples and see if serial monitor print and read serial messages.
OR you can try your Arduino with Ardulink Console (http://www.ardulink.org/screen-shots/). You have just to download Ardulink (Ardulink), upload a sketch inside the zip and run ardulink.bat or ardulink.sh depending on you operating system. It works even with a Raspberry PI. This software uses Ardulink that is a java open source library to communicate with a PC to an Arduino. It's very simple to use. I've written it so if you want I can give to you some assistance. Ardulink can communicate also with some arduino clones that not use serial communication.