firmata, ping sensor, arduino, and OF problem

i coming pure data had ping sensor sending distance in inches pure data used distance information play video , different speeds.

i'd same in of because of handles video better.

i getting hung on getting arduino send distance information of. distance in inches should show in serial monitor of arduino software, jumble data.

here code have on arduino (.pde file):

code: [select]

#include <firmata.h>

byte digitalpin;
char firstchar;
char secondchar;
int pingpin = 7;

void digitalwritecallback(byte pin, int value)
{
   pinmode(pin,output);
   analogwrite(pin, value);
}

void setup()
{
   firmata.setfirmwareversion(0, 1);
   firmata.attach(analog_message, digitalwritecallback);
   firmata.begin();
}

void loop()
{
   while(firmata.available()) {
       firmata.processinput();
   }
   for(digitalpin = 0; digitalpin < total_digital_pins; digitalpin++) {
     if(digitalpin == 7)  
       firmata.senddigitalport(digitalpin, computedistance());
   }
}

long computedistance(){
long duration, inches, cm;
  // ping))) triggered high pulse of 2 or more microseconds.
 // give short low pulse beforehand ensure clean high pulse.
 pinmode(pingpin, output);
 digitalwrite(pingpin, low);
 delaymicroseconds(2);
 digitalwrite(pingpin, high);
 delaymicroseconds(5);
 digitalwrite(pingpin, low);

 // same pin used read signal ping))): high
 // pulse duration time (in microseconds) sending
 // of ping reception of echo off of object.
 pinmode(pingpin, input);
 duration = pulsein(pingpin, high);

 // convert time distance
 return microsecondstoinches(duration);
 //cm = microsecondstocentimeters(duration);
 
}

long microsecondstoinches(long microseconds)
{
 // according parallax's datasheet ping))), there are
 // 73.746 microseconds per inch (i.e. sound travels @ 1130 feet per
 // second).  this gives distance travelled ping, outbound
 // , return, divide 2 distance of obstacle.
 return microseconds / 74 / 2;
}

long microsecondstocentimeters(long microseconds)
{
 // speed of sound 340 m/s or 29 microseconds per centimeter.
 // ping travels out , back, find distance of the
 // object take half of distance travelled.
 return microseconds / 29 / 2;
}


once distance data show in serial monitor firmata, move on getting of read data.

i have scoured internet examples deal analog data. ping sensor digital need able receive digital data in of...

any insights appreciated!!

thanks
tim

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