parallax ping sensor and firmata

I was able to send distance data pretty easily to Pure Data via the SimpleMessageSystem. All that simplicity went out the window when switching to OF and Firmata on the arduino.

I need to send distance data to OF. The below code gets me a value of -1 but I need an int sent back to OF.

One of my problems is that I am confused by sending and receiving Analog or Digital data. The Ping sensor plugs into digital pin #7. But since the inches are computed as an int, should I send back to OF as analog?

here is my code:

#include <Firmata.h>

byte digitalPin;
char firstChar; 
char secondChar;
int pingPin = 7;


void setup()
{
    Firmata.begin(57600);
}

void loop()
{
   while(Firmata.available()) {
      Firmata.processInput();
   }

   //Firmata.sendDigitalPort(pingPin, computeDistance());
   Firmata.sendAnalog(pingPin, computeDistance());
}

long computeDistance(){
 long duration, inches, cm;
   // The PING))) is triggered by a HIGH pulse of 2 or more microseconds.
  // We give a short LOW pulse beforehand to ensure a clean HIGH pulse.
  pinMode(pingPin, OUTPUT);
  digitalWrite(pingPin, LOW);
  delayMicroseconds(2);
  digitalWrite(pingPin, HIGH);
  delayMicroseconds(5);
  digitalWrite(pingPin, LOW);

  // The same pin is used to read the signal from the PING))): a HIGH
  // pulse whose duration is the time (in microseconds) from the sending
  // of the ping to the reception of its echo off of an object.
  pinMode(pingPin, INPUT);
  duration = pulseIn(pingPin, HIGH);

  // convert the time into a distance
  return microsecondsToInches(duration);
  //cm = microsecondsToCentimeters(duration);
  
}

long microsecondsToInches(long microseconds)
{
  // According to Parallax's datasheet for the PING))), there are
  // 73.746 microseconds per inch (i.e. sound travels at 1130 feet per
  // second).  This gives the distance travelled by the ping, outbound
  // and return, so we divide by 2 to get the distance of the obstacle.
  // See: http://www.parallax.com/dl/docs/prod/acc/28015-PING-v1.3.pdf
  return microseconds / 74 / 2;
}

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

thanks for your help!

got it with Firmata.sendAnalog(); on the arduino and arduino.getAnalog(); on the OF side...