package altimeter;
import gnu.io.CommPortIdentifier;
import gnu.io.PortInUseException;
import gnu.io.SerialPort;
import gnu.io.UnsupportedCommOperationException;
import java.io.FileNotFoundException;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.io.PrintStream;
import java.nio.charset.Charset;
import java.text.DateFormat;
import java.util.ArrayList;
import java.util.Date;
import java.util.Enumeration;
import java.util.TimeZone;
/**
* Class to interface the PerfectFlite Alt15K/WD altimeter.
*
* Also includes a main method that retrieves all flight profiles and saves them to files.
*
* @author Sampo Niskanen <sampo.niskanen@iki.fi>
*/
public class Alt15K {
public static final int TIMEOUT = 500;
public static final int RWDELAY = 5;
private static final boolean DEBUG = false;
private static final Charset CHARSET = Charset.forName("ISO-8859-1");
private final CommPortIdentifier portID;
private SerialPort port = null;
private InputStream is = null;
private OutputStream os = null;
public static String[] getNames() {
ArrayList<String> list = new ArrayList<String>();;
Enumeration<?> pids = CommPortIdentifier.getPortIdentifiers();
while (pids.hasMoreElements()) {
CommPortIdentifier pid = (CommPortIdentifier) pids.nextElement();
if (pid.getPortType() == CommPortIdentifier.PORT_SERIAL)
list.add(pid.getName());
}
return list.toArray(new String[0]);
}
public Alt15K(String name) throws IOException {
CommPortIdentifier pID = null;
Enumeration<?> portIdentifiers = CommPortIdentifier.getPortIdentifiers();
while (portIdentifiers.hasMoreElements()) {
CommPortIdentifier pid = (CommPortIdentifier) portIdentifiers.nextElement();
if(pid.getPortType() == CommPortIdentifier.PORT_SERIAL &&
pid.getName().equals(name)) {
pID = pid;
break;
}
}
if (pID==null) {
throw new IOException("Port '"+name+"' not found.");
}
this.portID = pID;
}
/**
* Get altimeter flight data. The flight profile is chosen by the parameter n,
* 0 = latest flight, 1 = second latest, etc.
*
* @param n Which flight profile to use (0=newest, 1=second newest, etc)
* @return The altimeter flight data
* @throws IOException in case of IOException
* @throws PortInUseException in case of PortInUseException
*/
public AltData getData(int n) throws IOException, PortInUseException {
AltData alt = new AltData();
ArrayList<Integer> data = new ArrayList<Integer>();
byte[] buf;
byte[] buf2 = new byte[0];
boolean identical = false; // Whether identical lines have been read
if (DEBUG)
System.out.println(" Retrieving altimeter data n="+n);
try {
open();
// Get version and position data
byte[] ver = getVersionData();
alt.setVersion(new byte[] { ver[0],ver[1] });
// Calculate the position requested
if (n > 2)
n = 2;
int position = ver[2] - n;
while (position < 0)
position += 3;
if (DEBUG)
System.out.println(" Requesting data from position "+position);
// Request the data
write("D");
write((byte)position);
write("PS");
sleep();
// Read preliminary data
buf = read(4);
int msl_level = combine(buf[0],buf[1]);
int datacount = combine(buf[2],buf[3]);
if (DEBUG)
System.out.println(" Preliminary data msl="+msl_level+" count="+datacount);
alt.setMslLevel(msl_level-6000);
alt.setDataSamples(datacount);
if (DEBUG)
System.out.println(" Retrieving "+datacount+" samples");
long t = System.currentTimeMillis();
int count = 0;
while (count < datacount) {
sleep();
write("G");
sleep();
buf = read(17);
if (buf.length == 17) {
// Checksum = sum of all bytes + 1
// (signedness does not change the result)
byte checksum = 1;
for (int i=0; i<16; i++)
checksum += buf[i];
if (checksum != buf[16]) {
printBytes("ERROR: Checksum fail on data (computed="+checksum+
" orig="+buf[16]+")",buf);
System.out.println("Ignoring error");
}
} else {
System.err.println("ERROR: Only "+buf.length+" bytes read, should be 17");
}
for (int i=0; i<buf.length-1; i+=2) {
data.add(combine(buf[i],buf[i+1]));
count++;
}
/*
* Check whether the data is identical to the previous data batch. If reading
* too fast, the data seems to become duplicated in the transfer. We need to check
* whether this has happened by attempting to read more data than is normally
* available.
*/
int c, l=Math.min(buf.length, buf2.length);
for (c=0; c<l; c++) {
if (buf[c] != buf2[c])
break;
}
if (c==l && buf.length == buf2.length)
identical = true;
buf2 = buf.clone();
}
if (DEBUG)
System.out.println(" Retrieved "+data.size()+" samples in "+
(System.currentTimeMillis()-t)+" ms");
// In case of identical lines, check for more data. This would mean that the
// transfer was corrupted.
if (identical) {
System.err.println("WARNING: Duplicate data detected, possible error");
}
// Test for more data
if (DEBUG)
System.out.println(" Testing for more data");
sleep();
write("G");
sleep();
buf = read(17);
if (buf.length > 0) {
System.err.println("ERROR: Data available after transfer! (length="+buf.length+")");
}
// Create an int[] array and set it
int[] d = new int[data.size()];
for (int i=0; i<d.length; i++)
d[i] = data.get(i);
alt.setData(d);
// Catch all exceptions, close the port and re-throw the exception
} catch (PortInUseException e) {
close();
throw e;
} catch (IOException e) {
close();
throw e;
} catch (UnsupportedCommOperationException e) {
close();
throw new RuntimeException("Required function of RxTx library not supported",e);
} catch (RuntimeException e) {
// Catch-all for all other types of exceptions
close();
throw e;
}
close();
return alt;
}
private byte[] getVersionData() throws PortInUseException, IOException,
UnsupportedCommOperationException {
byte[] ver = new byte[3];
byte[] buf;
if (DEBUG)
System.out.println(" Retrieving altimeter version information");
// Signal to altimeter we are here
write((byte)0);
sleep(15); // Sleep for 15ms, data is incoming at 10 samples/sec
// Get altimeter version, skip zeros
write("PV");
sleep();
buf = readSkipZero(2);
sleep();
if (buf.length != 2) {
close();
throw new IOException("Communication with altimeter failed.");
}
ver[0] = buf[0];
ver[1] = buf[1];
// Get position of newest data
write("M");
sleep();
buf = read(1);
if (buf.length != 1) {
close();
throw new IOException("Communication with altimeter failed.");
}
ver[2] = buf[0];
if (DEBUG)
System.out.println(" Received version info "+ver[0]+"."+ver[1]+", position "+ver[2]);
return ver;
}
/**
* Delay the communication by a small delay (RWDELAY ms).
*/
private void sleep() {
sleep(RWDELAY);
}
/**
* Sleep for the given amount of milliseconds.
*/
private void sleep(int n) {
try {
Thread.sleep(n);
} catch (InterruptedException ignore) { }
}
private void open()
throws PortInUseException, IOException, UnsupportedCommOperationException {
if (port != null) {
System.err.println("ERROR: open() called with port="+port);
Thread.dumpStack();
close();
}
if (DEBUG) {
System.out.println(" Opening port...");
}
port = (SerialPort)portID.open("OpenRocket",1000);
port.setSerialPortParams(9600, SerialPort.DATABITS_8, SerialPort.STOPBITS_1,
SerialPort.PARITY_NONE);
port.setInputBufferSize(1);
port.setOutputBufferSize(1);
port.enableReceiveTimeout(TIMEOUT);
is = port.getInputStream();
os = port.getOutputStream();
}
private byte[] readSkipZero(int n) throws IOException, UnsupportedCommOperationException {
long t = System.currentTimeMillis() + TIMEOUT*2;
if (DEBUG) {
System.out.println(" readSkipZero "+n+" bytes");
}
while (System.currentTimeMillis() < t) {
byte[] buf = read(n);
if (DEBUG)
printBytes(" Received",buf);
if (buf.length == 0) // No data available
return buf;
// Skip zeros
int i;
for (i=0; i<buf.length; i++)
if (buf[i] != 0)
break;
if (i==0) // No zeros to skip
return buf;
if (i < buf.length) {
// Partially read
int count = buf.length-i; // No. of data bytes
byte[] array = new byte[n];
System.arraycopy(buf, i, array, 0, count);
buf = read(n-count);
if (DEBUG)
printBytes(" Received (partial)",buf);
System.arraycopy(buf, 0, array, count, buf.length);
if (DEBUG)
printBytes(" Returning",array);
return array;
}
}
if (DEBUG)
System.out.println(" No data read, returning empty");
return new byte[0]; // no data, only zeros
}
private byte[] read(int n) throws IOException, UnsupportedCommOperationException {
byte[] bytes = new byte[n];
port.enableReceiveThreshold(n);
long t = System.currentTimeMillis() + TIMEOUT;
int count = 0;
if (DEBUG)
System.out.println(" Reading "+n+" bytes");
while (count < n && System.currentTimeMillis() < t) {
byte[] buf = new byte[n-count];
int c = is.read(buf);
System.arraycopy(buf, 0, bytes, count, c);
count += c;
}
byte[] array = new byte[count];
System.arraycopy(bytes, 0, array, 0, count);
if (DEBUG)
printBytes(" Returning",array);
return array;
}
private void write(String s) throws IOException {
write(s.getBytes(CHARSET));
}
private void write(byte ... bytes) throws IOException {
if (DEBUG)
printBytes(" Writing",bytes);
os.write(bytes);
}
private void close() {
if (DEBUG)
System.out.println(" Closing port");
SerialPort p = port;
port = null;
is = null;
os = null;
if (p != null)
p.close();
}
public static void main(String[] arg) {
if (arg.length != 1) {
System.err.println("Usage: java Alt15K <basename>");
System.err.println("Files will be saved <basename>-old.log, -med and -new");
return;
}
String device = null;
String[] devices = Alt15K.getNames();
for (int i=0; i<devices.length; i++) {
if (devices[i].matches(".*USB.*")) {
device = devices[i];
break;
}
}
if (device == null) {
System.out.println("Device not found.");
return;
}
System.out.println("Selected device "+device);
AltData alt = null;
String file;
try {
Alt15K p = new Alt15K(device);
System.out.println("Retrieving newest data...");
alt = p.getData(0);
System.out.println("Apogee at "+alt.getApogee()+" feet");
file = arg[0]+"-new.log";
System.out.println("Saving data to "+file+"...");
savefile(file,alt);
System.out.println("Retrieving medium data...");
alt = p.getData(1);
System.out.println("Apogee at "+alt.getApogee()+" feet");
file = arg[0]+"-med.log";
System.out.println("Saving data to "+file+"...");
savefile(file,alt);
System.out.println("Retrieving oldest data...");
alt = p.getData(2);
System.out.println("Apogee at "+alt.getApogee()+" feet");
file = arg[0]+"-old.log";
System.out.println("Saving data to "+file+"...");
savefile(file,alt);
} catch (IOException e) {
e.printStackTrace();
} catch (PortInUseException e) {
e.printStackTrace();
}
// System.out.println(alt);
// alt.printData();
}
static private void savefile(String file, AltData data) throws FileNotFoundException {
PrintStream output = new PrintStream(file);
// WTF is this so difficult?!?
DateFormat fmt = DateFormat.getDateTimeInstance(DateFormat.MEDIUM, DateFormat.MEDIUM);
TimeZone tz=TimeZone.getTimeZone("GMT+3");
fmt.setTimeZone(tz);
output.println("# Alt15K data, file "+file);
output.println("# Data retrieved at: "+fmt.format(new Date()));
output.println("# Values are in feet above launch level");
output.println("# ");
output.println("# Apogee = "+data.getApogee());
output.println("# MSL level = "+data.getMslLevel());
output.println("# Data count = "+data.getDataSamples());
byte[] b = data.getVersion();
String s="";
for (int i=0; i<b.length; i++) {
if (s.equals(""))
s = ""+((int)b[i]);
else
s = s+"."+((int)b[i]);
}
output.println("# Altimeter version = " + s);
int[] values = data.getData();
for (int i=0; i < values.length; i++) {
output.println(""+values[i]);
}
output.close();
}
static private void printBytes(String str, byte[] b) {
printBytes(str, b,b.length);
}
static private void printBytes(String str, byte[] b, int n) {
String s;
s = str+" "+n+" bytes:";
for (int i=0; i<n; i++) {
s += " "+unsign(b[i]);
}
System.out.println(s);
}
static private int unsign(byte b) {
if (b >= 0)
return b;
else
return 256 + b;
}
@SuppressWarnings("unused")
static private int combine(int a, int b) {
return 256*a + b;
}
static private int combine(byte a, byte b) {
int val = 256*unsign(a)+unsign(b);
if (val <= 32767)
return val;
else
return val-65536;
}
}