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Topic: Messenger library (Read 28410 times) previous topic - next topic

tof

Messenger is probably not the best solution if you are sending all that data at a high interval. For 64 leds, each controlled through three numbers separated by commas, you are looking at at least 384 bytes of data! This should definitely cause some Messenger overflows. Even without the overflow, you would expect an update speed between 15 and 5 "images" per second.

The best solution is to simply send a bunch of bytes without the help of Messenger. Here is partial code (I did not test it):

Code: [Select]
#define VALUES 192 //64*3
byte leds[VALUES];

unsigned long lastTime;
int writeindex;

void setup() {
 
 Serial.begin(57600);
 lastTime = millis();
 writeindex = 0;
}

void loop() {

// Read serial data
 while ( Serial.available() ) {
   // if ever there is more than 10ms between two bytes,
   // this indicates the start of a new series
    if( millis() - lastTime > 10) {
     writeindex = 0;  
   }
   lastTime= millis();
   leds[writeindex] = (byte) Serial.read();
   writeindex = (writeindex + 1) % VALUES;

 }
 
 /*
 For example, you want to retrieve the value of led i
 red = leds[i*3];
 green = leds[(i*3)+1];
 blue = leds[(i*3)+2];
 */
 
}
Thomas Ouellet Fredericks

basuraman

oh right...well i was just trying to see if it would work at all - then was going to try to optimize it or use other techniques to get it going faster. but you have a great point - keeping the data stream lean from the get go will save alot of overhead and make everything faster for sure.

i guess i started with Messenger because my host software sending from the PC easily spits out strings, but i had a harder time getting it to send raw ascii bytes - as strange as that may sound. i'll try retooling it and give it a go with your code as an example.

thanks so much!

diode

Hi Tof,
This looks really interesting. Could you perhaps outline what the best method and format of sending a combined message from Processing would be, to match your Arduino receiving example at http://www.arduino.cc/playground/Code/Messenger?
For example to send an array or string like (114,134,144,116,84,126,143)
Thanks!

bigRed

Quote
Hi Tof,
This looks really interesting. Could you perhaps outline what the best method and format of sending a combined message from Processing would be, to match your Arduino receiving example at http://www.arduino.cc/playground/Code/Messenger?
For example to send an array or string like (114,134,144,116,84,126,143)
Thanks!


I also have this question, I've tried writing to the serial port that the arduino is hooked up to, but that doesn't work very well.

tof

Hi diode and bigRed,

Quote
Could you perhaps outline what the best method and format of sending a combined message from Processing would be, to match your Arduino receiving example at http://www.arduino.cc/playground/Code/Messenger


Well, the simplest solution would be to instantiate a Serial object and then write the data as ASCII ints to it.

For example, this is the Processing code that would send the array {114,134,144,116,84,126,143} to the Messenger enabled Arduino:

Code: [Select]
import processing.serial.*;

Serial serial;  // Create object from Serial class

int[] data = {114,134,144,116,84,126,143};

void setup()
{
 size(200, 200);
 // I know that the first port in the serial list on my mac
 // is always my  FTDI adaptor, so I open Serial.list()[0].
 // On Windows machines, this generally opens COM1.
 // Open whatever port is the one you're using.

 for ( int i=0; i < Serial.list().length ; i ++ ) {
     println("Port: \t"+Serial.list()[i]);
 }
 String portName = Serial.list()[0];
 serial = new Serial(this, portName, 115200);
 frameRate(20);
}

void draw() {
 
 // Send the data.
 // The data can not be formed of more than 64 ASCII characters.
 
 for (int i=0; i < data.length ; i++ ) {
    serial.write(str(data[i])); // Write the data as an ASCII character
    serial.write(' '); // Write the word separator: an ASCII space character
 }
 // Write the message terminator: an ASCII carriage return.
 serial.write('\r');
 

 
}
Thomas Ouellet Fredericks

sts

Hi!

I am communicating between PC and Arduino using your messenger protocol and so far it is great. But now I am trying to send a whole text-array and found something strange:
Whenever I send a message from PC to Arduino that has 64 or more characters the message gets lost. Just so you can have some fun looking at my 'totally awesome' coding skills, here is what I'm using:

Code: [Select]

void messageCompleted() {
 // This loop will echo each element of the message separately
 byte i;
 byte j;
 while ( message.available() ) {
   message.copyString(MsgrString,MAXSIZE);
   // Serial.print(MsgrString); // Echo the string
   // Serial.println(); // Terminate the message with a carriage return
   
   if (!strcmp(MsgrString,"?")) {            // Somebody wants us to SEND data
     while ( message.available() ) {
       message.copyString(MsgrString,MAXSIZE);
       // Serial.print(MsgrString); // Echo the string
       // Serial.println(); // Terminate the message with a carriage return
     
       if (!strcmp(MsgrString,"RoomName")) {            // We need to send the RoomName array
         //Serial.println("Sending RoomName array");
         for (i=0; i<8; i++){
           //Serial.print(i, DEC);
           Serial.print(RoomName[i]);
           Serial.print(" ");
           
         }
         Serial.println();
       }
       if (!strcmp(MsgrString,"Mode")) {            // We need to send the Mode byte
         //Serial.println("Sending Mode");
         Serial.print("Mode=");
         Serial.println(Mode, DEC);
       }        
     }
   }
   
   if (!strcmp(MsgrString,"!")) {            // Somebody wants us to RECEIVE data
     while ( message.available() ) {
       message.copyString(MsgrString,MAXSIZE);
       //Serial.print(MsgrString); // Echo the string
       //Serial.println(); // Terminate the message with a carriage return
     
       if (!strcmp(MsgrString,"RoomName")) {            // We need to receive the RoomName array
         //Serial.println("Receiving RoomName array");
         i=0;
         while ( message.available() ) {
           message.copyString(MsgrString,MAXSIZE);
           //Serial.print(MsgrString); // Echo the string
           //Serial.println(); // Terminate the message with a carriage return
           for (j=0; j<10; j++){
             RoomName[i][j] = MsgrString[j];
           }
           Serial.print(i, DEC);
           //Serial.println(RoomName[i]);
           i++;
         }
         Serial.println("RoomName array:");
         for (i=0; i<8; i++){
           Serial.print(i, DEC);
           Serial.print(" ");
           //Serial.println(RoomName[i]);
         }
       }
       else if (!strcmp(MsgrString,"Mode")) {            // We need to receive the Mode byte
         while ( message.available() ) {
           Serial.println("receiving Mode");
           Mode = message.readInt();
           Serial.print("I received: ");
           Serial.println(Mode, DEC);
         }
       }
     }
   }        
 }


Is there a 64 character limitation? Or is the problem somehow on my side?

BTW: MAXSIZE is 255.

Thanks for a great library!

Stefan

Beankyu

I find find it really helpful :)

sts

Never mind about the 64 character limit. I found the offending code after all of about 30 seconds search. Sometimes using your own eyes is perfectly sufficient!

Code: [Select]
#define MESSENGERBUFFERSIZE 64

changed to

Code: [Select]
#define MESSENGERBUFFERSIZE 128

duh!

Hi, just for your information.

I've made a description in how to send serial data from and to Flash with the Messenger library. The file can be used with the basic_communication sketch in the Messenger library examples folder.
http://
http://www.kasperkamperman.com/blog/arduino-flash-communication-as3-messenger/
.


mikemikemike

Im new to arduino and loving it!

luke123

Hey thanks for posting this library !  Im having a problem though ..


Using the example checkstring  I can turn the led on and off fine :)  but if i type some random letters ect it will confuse it and will stop it working totally the next time i type "on" ect.

I need this to ignore anything other than "on" or "off" ect ?







Code: [Select]
// This example demonstrates Messenger's checkString method
// It turns on the LED attached to pin 13 if it receives "on"
// It turns it off if it receives "off"


#include <Messenger.h>


// Instantiate Messenger object with the message function and the default separator
// (the space character)
Messenger message = Messenger();


// Define messenger function
void messageCompleted() {
 // This loop will echo each element of the message separately
 while ( message.available() ) {
 
 
   
 
 
   if ( message.checkString("on") ) {
     digitalWrite(13,HIGH);
   } else if ( message.checkString("off") ) {
     digitalWrite(13,LOW);
   }
 }
 
 
}

void setup() {
 // Initiate Serial Communication
 Serial.begin(115200);
 message.attach(messageCompleted);
 
 pinMode(13,OUTPUT);
 
}

void loop() {
 
 // The following line is the most effective way of
 // feeding the serial data to Messenger
 while ( Serial.available() ) message.process( Serial.read() );


}// This example demonstrates Messenger's checkString method
// It turns on the LED attached to pin 13 if it receives "on"
// It turns it off if it receives "off"


#include <Messenger.h>


// Instantiate Messenger object with the message function and the default separator
// (the space character)
Messenger message = Messenger();


// Define messenger function
void messageCompleted() {
 // This loop will echo each element of the message separately
 while ( message.available() ) {
 
 
   
 
 
   if ( message.checkString("on") ) {
     digitalWrite(13,HIGH);
   } else if ( message.checkString("off") ) {
     digitalWrite(13,LOW);
   }
 }
 
 
}

void setup() {
 // Initiate Serial Communication
 Serial.begin(115200);
 message.attach(messageCompleted);
 
 pinMode(13,OUTPUT);
 
}

void loop() {
 
 // The following line is the most effective way of
 // feeding the serial data to Messenger
 while ( Serial.available() ) message.process( Serial.read() );


}

LAVco

#56
Jul 22, 2010, 06:25 pm Last Edit: Jul 22, 2010, 08:32 pm by LAVco Reason: 1
This library came in handy for me and thought that I would share a nifty function addition (checkSubString).

In this project's case the serial port is used to send data and to receive poll and configuration settings commands.

For example;

Poll Commands (e.g. send a poll command to Arduino to receive data from a client computer over serial):
M0!
where:
- M0 is message type 0

M1!
where:
- M1 is message type 1


Configuration Settings:
SET01nn
where:
- nn set the sample interval in seconds (01-60)
.
.
.
SET08nn
where:
- nn = 96 sets the serial port's baud-rate to 9600
- nn = 38 sets the serial port's baud-rate to 38400

Code: [Select]

Messenger.h (Public)
uint8_t checkSubString(char *subString, char *string, uint8_t length);

Messenger.cpp
// alpha implementation, may be a more efficient method
// instead of calling strncpy
uint8_t Messenger::checkSubString(char *subString, char *string, uint8_t length) {
     if (next()) {
           if ( strcasestr(subString,current) == 0 ) {
                 // return remaining chars after subString
                 int nChars = strlen(current) - strlen(subString);
                 strncpy(string, current + strlen(subString), nChars);
                 string[nChars] = '\0';
                       if ( strlen(string) > length ) return 0;
                 dumped = 1;
                 return 1;
           } else {
                 return 0;
           }
     }
}


Here is a usage example - simply add the following snippet example to the checkString example.

Code: [Select]

char buffer[32]; // global buffer


   } else if ( message.checkString("M0!") ) {
      // send message 0 data
   } else if ( message.checkSubString("SET01", buffer, 2) ) {
     Serial.print("Sample Interval: ");
     Serial.println(buffer);
    //
    // store sample interval...
   } else if ( message.checkSubString("SET08", buffer, 2) ) {
     Serial.print("Baud-Rate: ");
     Serial.println(buffer);
    //
    // store serial port baud-rate..
   } else {
     return;
   }


Enjoy!

Eric




Common sense is not so common...

LAVco

Hey luke123

Take a look at my post.  Simply add an "else" statement to return if no matches are found.

Cheers..

Eric
Common sense is not so common...

LAVco

Update to my previous post for checkSubString.

Code: [Select]

uint8_t Messenger::checkSubString(char *subString, char *string, uint8_t length) {
     if (next()) {
           //if ( strcasestr(subString,current) == 0 ) {
           if ( strstr(current, subString) != NULL ) {
                 // return remaining chars after subString
                 int nChars = strlen(current) - strlen(subString);
                 strncpy(string, current + strlen(subString), nChars);
                 string[nChars] = '\0';
                 if ( strlen(string) > length ) return 0;
                 dumped = 1;
                 return 1;
           } else {
                 return 0;
           }
     }
}


Cheers,

Eric
Common sense is not so common...

lorenzop

#59
Aug 02, 2010, 08:44 am Last Edit: Aug 02, 2010, 08:48 am by lorenzop Reason: 1
I'm having some trouble with bad commands. the correct commands for my project work great, but if I enter a command wrong it seems to lock up and the pin 13 led comes on. my code is still pretty simple and I don't see how it could cause this, and I don't see how the library could do it directly either. could it be an overflow someplace?

here's my code
http://download.growcontrol.com/arduino/usbmessenger.pde

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