[strider3700]

Ok getting data logging going on even at the simplest level turned out to be stupidly difficult for me. I've only been programming for a couple of decades now but I don't think I've ever touched the serial port so I decided to just grab an example someone else did and go with that.

My initial goal is just to get it writing every output to a local file. Nothing hard at all right?

Well I first tried a simple batch script that just monitored the serial port but that got a lot of corrupted crap or dropped data. So I figured since the arduino is using python lets just find a python script and do that. Well 4 hours and 5 examples later it wasn't working correctly. Once again lots of errors and corrupted data. I'm also not a python guy so debugging not knowing the language was a nightmare.

So I went to java which isn't my day to day but I've done a bunch of and it's damn close to c# which I mostly do these days. Then I figured since I have a java example lets learn eclipse, I've heard good things about it. Well it's pretty and shiny but it took me awhile to figure out how to add a jar to the project to make the rxtx library work. Anyways here's the code I found after I changed the port to be correct

package datalogger;

	import java.io.InputStream;
	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/ttyUSB0", // Linux
								};
		/** Buffered input stream from the port */
		private InputStream 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() {
			CommPortIdentifier portId = null;
			Enumeration portEnum = CommPortIdentifier.getPortIdentifiers();

			// iterate through, looking for the port
			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 = 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 {
					int available = input.available();
					byte chunk[] = new byte[available];
					input.read(chunk, 0, available);

					// Displayed results are codepage dependent
					System.out.print(new String(chunk));
				} 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) {
		SerialTest main = new SerialTest();
		main.initialize();
		System.out.println("Started");
	}

}

I got it from here. Arduino playground - Java
I like that it's event driven it totally gets rid of all those issues I had with the other attempts. Anyways the hard part was adding the rxtx jar recognized in eclipse. I followed this partially (it's for windows I'm on linux) Using RXTX In Eclipse - Rxtx. That got it working so I can now go back to some old school reading and writing to disk...

I think the major Issue I've had with getting this part working is there are hundreds of ways to do it and none of them are amazingly well documented. The arduino people of course don't recommend one method over another and google will net you thousands of partial chunks of code pointing you in the right direction but none of them are plug and play.