How to check if a string is on the serial port ??

ok ive got modem outputing data arduino .

example want turn led on if "led_on" sent on serial port. need buffer clear on every cr , ignore incorrect strings , reset.

because messenger method works if type incorrect string in seems stop working untill reset . im guessing buffer needs reset after each cr.



ive found 2 way of doing both problems , can me have working 1 ?



code 1 ,  i found example of reading data serial buffer , cant check if string in buffer .

code: [select]




#define strlen 16

char buffer[strlen];
int  bufferindex = 0;

void setup()
{
 serial.begin(9600);
}

void loop()
{
 if( serial.available())
 {
   char ch = serial.read();
   if( ch == '\r')  // terminating carriage return
   {
     buffer[ bufferindex ] = 0; // terminate string 0      bufferindex = 0;  // reset index ready string
     // string


if (buffer =="led_on"){               // put in  it doesnt work!

 serial.println("led on");
}



   }
   else
     buffer[ bufferindex++ ] = ch; // add character buffer
 }
}






code 2

this messenger's library checkstring method , work if send other set commard random text confuses untill reset it. seems clears buffer after match ect.

i need except other strings , turn led on when "on"  is sent.

code: [select]

// example demonstrates messenger's checkstring method
// turns on led attached pin 13 if receives "on"
// turns off if receives "off"


#include <messenger.h>


// instantiate messenger object message function , default separator
// (the space character)
messenger message = messenger();


// define messenger function
void messagecompleted() {
 // loop echo each element of 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() {
 
 // following line effective way of
 // feeding serial data messenger
 while ( serial.available() ) message.process( serial.read() );


}



any or examples great , reading

luke

in first code, collecting characters read serial port array, , null terminating string. good.

the problem comparison. == operator needs objects, not arrays of objects, on either side.

to compare strings, strings needs null terminated (as yours are), , need use strcmp function:

code: [select]

if(strcmp(buffer, "led_on") == 0) // if strcmp returns 0, strings match
{
  // turn led on
}

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