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How to let a sound play once in Processing?

import processing.serial.*;
import processing.sound.*;
SoundFile file;
Serial myPort; // Create object from Serial class
String val; // Data received from the serial port
//String antwoord = "A";
void setup()
{
size(300,300);
// I know that the first port in the serial list on my mac
// is Serial.list()[0].
// On Windows machines, this generally opens COM1.
// Open whatever port is the one you're using.
String portName = Serial.list()[0]; //change the 0 to a 1 or 2 etc. to match your port
myPort = new Serial(this, portName, 9600);
}
void draw()
{
if ( myPort.available() > 0)
{ // If data is available,
val = trim( myPort.readStringUntil(ENTER) );
// read it and store it in val
}
//println(val); //print it out in the console
file = new SoundFile(this,"Promise.mp3");
if ("A".equals(val) == true && file.isPlaying() == false) {
file.play();
file.amp(0.2);}
else{
ellipse(40,40,40,40);
}
}
I got this code, but I want the sound to keep playing as long as the signal 'A' is given. Now it starts playing constantly, which leads to a weird static noise. How can I make it just play steadidly?

You're creating a new SoundFile in every run of draw. So file.isPlaying() will always return false. Only create a new SoundFile if you haven't already. The simplest solution is probably to move file = new SoundFile(this,"Promise.mp3"); into setup
Or you check or remember if you already loaded the file.

I am sorry if it is a bit disconnected but I recommend using minim or a different sound library instead of the processing one, since it causes a lot of problems in exporting (at least it had done so consistently for me).

How to increase the sound Volume Output in Webrtc

Am working on a webrtc android application and everything is working fine except two things...
which are;
switching the default sound output device from the Earpiece to Speaker and vice versa..
I have tried to use the code below from this stackoverflow thread but they are not working
audioManager = (AudioManager) this.activity.getSystemService(Context.AUDIO_SERVICE);
audioManager.setSpeakerphoneOn(true);
audioManager.setMode(AudioManager.MODE_IN_COMMUNICATION);
And improving the video performance, there is a lot of lagging in the video streams where even the stream hangs a lot. if there is any one who can help me on this too thanks a lot.
Below is my peerConnection configs
String fieldTrials = (PeerConnectionFactory.VIDEO_FRAME_EMIT_TRIAL + "/" + PeerConnectionFactory.TRIAL_ENABLED + "/");
PeerConnectionFactory.InitializationOptions initializationOptions =
PeerConnectionFactory.InitializationOptions.builder(this)
.setFieldTrials(fieldTrials)
.createInitializationOptions();
PeerConnectionFactory.initialize(initializationOptions);
//Create a new PeerConnectionFactory instance - using Hardware encoder and decoder.
PeerConnectionFactory.Options options = new PeerConnectionFactory.Options();
DefaultVideoEncoderFactory defaultVideoEncoderFactory = new DefaultVideoEncoderFactory(
rootEglBase.getEglBaseContext(), /* enableIntelVp8Encoder */true, /* enableH264HighProfile */true);
DefaultVideoDecoderFactory defaultVideoDecoderFactory = new DefaultVideoDecoderFactory(rootEglBase.getEglBaseContext());
peerConnectionFactory = PeerConnectionFactory.builder()
.setOptions(options)
.setVideoEncoderFactory(defaultVideoEncoderFactory)
.setVideoDecoderFactory(defaultVideoDecoderFactory)
.createPeerConnectionFactory();
Thanks

Need add this permission in manifest
<uses-permission android:name="android.permission.MODIFY_AUDIO_SETTINGS"/>

Create OBD2 MUT scanner by using Java FTDI lib - jd2xx - openport1.3 usb cable

I am trying to create a Java obd2 scanner app for my mitsubishi lancer mx 1997 which use MUTII protocol over OBD2. Can anybody help me to read MUT request codes using jd2xx library.
I have tried the below program, but it didn read engine RPM.
package lancerscan;
import jd2xx.JD2XX;
public class Test2 {
public static void main(String[] args) throws Exception {
JD2XX jd = new JD2XX();
jd.open(0);
jd.setBaudRate(38400);
jd.setDataCharacteristics(
8, JD2XX.STOP_BITS_1, JD2XX.PARITY_NONE);
jd.setFlowControl(
JD2XX.FLOW_NONE, 0, 0);
jd.setTimeouts(1000, 1000);
String msg = "21";
int ret = jd.write(msg.getBytes());
System.out.println(ret + " bytes sent.");
int rd = jd.read();
System.out.println(">>>" + rd);
int status = jd.getQueueStatus();
byte[] data = new byte[(int) status];
long lngBytesReturned = jd.read(data, 0, data.length);
System.out.println("======= " + lngBytesReturned);
}
}
MUT request code for Engine RPM is 0x21
more MUT request codes can be found here
similar C programs which works fine is here; main prjct files are here
Thanks,
harsha

First your using a different baud rate to that in the example. The example uses 15625 baud but you are using 38400 baud.
Secondly you are missing some of the setup commands. I am not sure if this will make a difference but its something that is different between your code and the example.
Mitsubishi require you to set the car ECU into diagnostic mode by sending 0x00 at a rate of 5 baud on one of the pins. On the OpenPort 1.3D cable this translates to setting the break to on for 1800 ms and then turning it off. You can see this is done with the ftdimut_init() command from the libftdimut.c file.
printf("Sending 0x00 at 5 baud\n");
printf("Break on......\n");
ftStatus = FT_SetBreakOn(ftdimut_ftHandle);
if(ftStatus != FT_OK) return ftStatus;
ftdimut_msleep(1800);
printf("Break off......\n");
ftStatus = FT_SetBreakOff(ftdimut_ftHandle);
if(ftStatus != FT_OK) return ftStatus;
The car ECU will then send you 4 bytes containing the ECU ID. This can then be used to check the ECU correctly entered diagnostic mode. You can see this in libftdimut.c.
ftStatus = FT_Read(ftdimut_ftHandle, buf, 4, &bytesRead);
if(ftStatus != FT_OK) return ftStatus;
if(bytesRead == 4) {
return FT_OK;
}
Now assuming that you got the 4 bytes back you can start to send the diagnostic codes such as 0x17 or 0x21.

I just saw your post on my blog, niallm answer is correct, you need to do a 5 baud init first which involves driving the KLine, you can use something like the 5 baud init posted in that answer, more info about the protocol:
http://evoecu.logic.net/wiki/MUT_Protocol
After getting a 4 byte response you can start sending requests at 15625 baud (I'm communicating with a 94 3000GT so the CEL light stops blinking), also in my case I send the converted values (0x21 = 33 decimal) as a byte array.

Jetty Pi4J I2C error oppening /dev/i2c-1

I'm trying to send data from Raspberry PI to Arduino via I2c.
When i execute the code with a stand alone java application i'm able to send and receive data with NO problem (the code bellow is giving me the expected result).
public static void main(String[] args) throws Exception {
// get I2C bus instance
final I2CBus bus = I2CFactory.getInstance(I2CBus.BUS_1);
I2CDevice arduino = bus.getDevice(0x04);
byte[] buffer = new byte[1];
buffer[0] = 1;
arduino.write(buffer, 0, buffer.length);
Thread.sleep(100);
buffer[0] = 0;
int number = arduino.read(buffer, 0, 1);
}
Then i try the same code, but this time it is inside a Servlet, using Jetty in the Raspberry Pi, and i get the following error:
java.io.IOException: Cannot open file handle for /dev/i2c-1 got -1 back.
at com.pi4j.io.i2c.impl.I2CBusImpl.<init>(I2CBusImpl.java:96)
at com.pi4j.io.i2c.impl.I2CBusImpl.getBus(I2CBusImpl.java:70)
at com.pi4j.io.i2c.I2CFactory.getInstance(I2CFactory.java:56)..
Does anyone know what may be happening?
Regards,

Could it be that in one case your process has sudo rights and it doesn't in the other case?

The answer is
I2CFactory.getInstance(I2CBus.BUS_0);
in some cases, the BUS is inverted so try this, i hope it helps :)

Creating an efficient way of sending integers over a network. TCP

How can I convert integer values to byte arrays and then send them over a byte stream to the client program which converts the byte array back to an integer?
My program is a pingpong game. Once run it creates a server which a client connects to over the internet using an object stream right now. All is working well, but it doesn't seem very efficient. By that I mean the ball is stuttering back and forth while it is trying to keep in sync via the update loop. I may have programmed it loosely, but it was the best I could come up with. I hope someone who knows a lot more about how this kind of thing works can help me clear some things up.
My question put straight. I need to know a better way to send the ball positions and player position over the internet more efficiently. Currently the time it takes is too long. Although, I could be updating it the wrong way.
The way the streams are constructed:
oostream = new ObjectOutputStream(new BufferedOutputStream(socket.getOutputStream()));
oostream.flush();
oistream = new ObjectInputStream(new BufferedInputStream(socket.getInputStream()));
This is player 2's update loop:
IntData id = new IntData();
while (running) {
id.ballx = ballx;
id.bally = bally;
id.player2Y = player2Y;
oostream.writeObject(id);
oostream.flush();
Thread.sleep(updaterate);
id = (IntData) oistream.readObject();
player1Y = id.player1Y;
ballx = id.ballx;
bally = id.bally;
}
Player 1 is the server host.
This is player 1's update loop:
IntData id = new IntData();
while (running) {
id = (IntData) oistream.readObject();
player2Y = id.player2Y;
ballx = id.ballx;
bally = id.bally;
Thread.sleep(updaterate);
id.ballx = ballx;
id.bally = bally;
id.player1Y = player1Y;
oostream.writeObject(id);
oostream.flush();
}

I suggest not using full serialization for simply primitives. use DataInputStream and the like instead:
dostream = new DataOutputStream(new BufferedOutputStream(socket.getOutputStream()));
distream = new DataInputStream(new BufferedInputStream(socket.getInputStream()));
Then read with:
ballx=distream.readInt();
bally=distream.readInt();
and write as:
dostream.writeInt(ballx);
dostream.writeInt(bally);
Also I suggest you not sleep awaiting data on both sides. Sleep on one and let the second simply await for a full set of data before transmitting by cutting out the Thread.sleep() there.

this is the function im using everytime for it
its pretty simple and works perfectly but the function is not rly needed (just very easy to use)
public static final byte[] parseIntToByteArray(int i){
byte[] b = {(byte)(i >> 24),
(byte)(i >> 16),
(byte)(i >> 8),
(byte)i};
return b;
}
to get it back:
int xy = (bytearray[0] << 24 | bytearray[1] << 16 | bytearray[2] << 8 | bytearray[3]);