Inexplicable serial problem

hey, guys, i'm faced problem can not seem take care of - or find what's causing it.
basically there's 1 arduino sending serially string !a18 , other arduino (this one) receiving it.

here's second arduino's code:

code: [select]


/*
* temperature , humidity server
* version 1.0a
* pedro tome'
*
* how works:
* basically, 1 master arduino receives data
* various slave arduinos have temperature
* , humidity sensors, uploaded to
* pachube.com account.
*
* code for:
* slave :: temperature , humidity
*/



/* temperature sensor's pre-commands */
#include <onewire.h>
onewire  ds(7);  // temperature sensor's pin 2 (output) connected arduino's pin d7

/* humidity sensor's pre-commands */
int humsensor_pin = 0;  // humidity sensor's pin 2 (output) connected arduino's pin a0
float max_voltage = 3.27;  // humidity sensor's output when: 100% humidity @ 0ºc
float zeropercentvoltage = 0.8;  // humidity sensor's output when: 0% humidity

/* other pre-comands */
int statusled = 2;  // status led connected pin d2 show whether sketch running or not
int rx_pin = 0;  // serial input pin d0
int tx_pin = 1;  // serial output pin d1
char selfaddressletter = 'a';  // letter 'a'. every arduino has different letter address (duh!).


void setup() {
 serial.begin(115200);
 pinmode(statusled, output);
 pinmode(rx_pin, input);
 pinmode(tx_pin, output);
}


void loop() {
 serial.flush();
 boolean stringvalid = false;  // initialize variable holds validity status of received strings
 byte receivedaddressletter[1] = {'/0'};  // initalize variable contains received address letter
 char receivedaddresscrc[2];  // initalize array contains received address crc, 2 characters long
 memset(receivedaddresscrc, '/0', 2);  // set addresscrc array null characters
 byte startbyte = '/0';  // initialize startbyte, first relevant character of received messages
 
 unsigned long starttime = millis();  // sets starttime = now
 int timeout = 1000;  // sets timout 1 second
 while (millis() - starttime < timeout && startbyte != '!') {
   startbyte = serial.read();
 }
 
 
 if (startbyte == '!') {  // if arduino has received serial message started character '!'
   unsigned long starttime = millis();  // set starttime = now
   int timeout = 1000;  // set timout 1 second
   while (millis() - starttime < timeout && serial.available() < 3) {
     ;  // wait buffer filled 3 characters while doing nothing
   }
   
   
   /* read received address , crc */
   receivedaddressletter[0] = serial.read();
   for (int i=0; < 2; i++) {
     receivedaddresscrc[i] = serial.read();
   }
   
   
   /* check validity of received content generating , comparing crcs */
   unsigned int intreceivedaddresscrc;
   intreceivedaddresscrc = htoi(receivedaddresscrc[0])*16+htoi(receivedaddresscrc[1]);  // convert crc array int
   
   if (intreceivedaddresscrc == generatecrc8(receivedaddressletter, 1)) {
     stringvalid = true;
     serial.println("the received string valid.");
   }
   else {
     stringvalid = false;
     serial.println("the received string not valid.");
   }
   
   
   /* check if receivedaddressletter matches arduino's selfaddressletter
      and, if so, collect data sensors , send master */
   if (stringvalid == true && receivedaddressletter[0] == selfaddressletter) {
     
    /*                        
     * temperature sensor code :: start
     */
     int highbyte, lowbyte, treading, signbit, tc_100;
     
     byte i;
     byte present = 0;
     byte data[12];
     byte addr[8];
     
     if ( !ds.search(addr)) {
       //serial.println("no more addresses.");
       ds.reset_search();
       delay(250);
       return;
     }
     
     if ( onewire::crc8( addr, 7) != addr[7]) {
         serial.println("crc not valid!");
         return;
     }
     
     if ( addr[0] != 0x28) {
         serial.println("device not ds18b20 family device.");
         return;
     }
     
     // dallastemperature library can work you!
     ds.reset();
     ds.select(addr);
     ds.write(0x44,1);  // start conversion, parasite power on @ end
     
     delay(900);  // maybe 750ms enough, maybe not
     // might ds.depower() here, reset take care of it.
     
     present = ds.reset();
     ds.select(addr);    
     ds.write(0xbe);  // read scratchpad
     
     for ( = 0; < 9; i++) {  // need 9 bytes
       data[i] = ds.read();
     }
     
     // converting hex readable data...
     lowbyte = data[0];
     highbyte = data[1];
     treading = (highbyte << 8) + lowbyte;
     signbit = treading & 0x8000;  // test sig bit
     if (signbit) // if negative
     {
       treading = (treading ^ 0xffff) + 1; // 2's comp
     }
     tc_100 = (6 * treading) + treading / 4;  // multiply (100 * 0.0625) or 6.25
     
   
     float floated_tc_100 = tc_100;  // floats can't divide ints, convert int float
     float ctemperature = floated_tc_100 / 100;
     if (signbit) // if it's negative
        {ctemperature = -1 * ctemperature;}
     
     //serial.print("tc_100: "); serial.println(tc_100);  // make sure ctemperature correct
     serial.print("temperature (celsius): "); serial.println(ctemperature);
     
    /*
     * temperature sensor code :: end
     */
   
     //--------------------------------------------------------------------------------------
     
    /*
     * humidity sensor code :: start
     */
     
     float humsensor_rawread = analogread(humsensor_pin);
     //serial.print("raw humidity value: "); serial.println(humsensor_rawread);
     
     max_voltage = (3.27-(0.006706*ctemperature));  // max voltage value drops 0.006705882 volts each ºc on 0ºc
     float rh = ((((humsensor_rawread/1023)*5)-zeropercentvoltage)/max_voltage)*100;
     
     serial.print("relative humidity (%): "); serial.println(rh);
     
    /*
     * humidity sensor code :: end
     */
     
     serial.println("loop end -------------------");
     serial.println();
     
   }  //end if (stringvalid == true && receivedaddressletter[0] == selfaddressletter)
 }  //end if (startbyte == '!')
}  //end void loop()



here's expected output:

code: [select]


the received string valid.
temperature (celsius): 16.62
relative humidity (%): 84.38
loop end -------------------

the received string valid.
temperature (celsius): 16.62
relative humidity (%): 83.76
loop end -------------------

the received string valid.
temperature (celsius): 16.62
relative humidity (%): 83.92
loop end -------------------

the received string valid.
temperature (celsius): 16.62
relative humidity (%): 83.61
loop end -------------------



and here's actual output:

code: [select]


the received string valid.
temperature (celsius): 16.62
relative humidity (%): 84.38
loop end -------------------

the received string valid.
the received string valid.
temperature (celsius): 16.62
relative humidity (%): 83.76
loop end -------------------

the received string valid.
the received string valid.
temperature (celsius): 16.62
relative humidity (%): 83.92
loop end -------------------

the received string valid.
the received string valid.
temperature (celsius): 16.62
relative humidity (%): 83.61
loop end -------------------



this think happening:
1. arduino receives string , follows code end.
2. arduino receives string , not follow code end.
3. arduino receives string , follows code end.
4. arduino receives string , not follow code end.
5. arduino receives string , follows code end.
6. etc.


so, can see problem? :/




oh, , happens 9600 baud rate.
i read in thread this:

quote

code: [select]

 serial.begin(9600);
this limiting factor. processing , arduino can talk faster this. try higher speed, 115200

so thought "hey, why hell not?" , turned baud rate up.
does higher baud rate offer more problems lower baud rate? master arduino , several slave arduinos supposed talk serially @ distance of approximately 300m (through rs485)...


thank you!

quote

does higher baud rate offer more problems lower baud rate?

it can more prone line noise, , corruption due cable capacitance.

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