I2C Arduino to Arduino, Send Ping( any sensors)Data to master?

Projects Networking, Protocols, and Devices
5

runman69:
thanks for the reply Australia

I am Nick Gammon:

I live in Australia:

You want to do something more like this:

#include <Wire.h>
const int pingPin = 7;

long duration, cm;

void setup()
{
  Wire.begin(2);                // join i2c bus with address #2
  Wire.onRequest(requestEvent); // register event
}

void loop()
{
  pinMode(pingPin, OUTPUT);
  digitalWrite(pingPin, LOW);
  delayMicroseconds(2);
  digitalWrite(pingPin, HIGH);
  delayMicroseconds(5);
  digitalWrite(pingPin, LOW);
  pinMode(pingPin, INPUT);
  duration = pulseIn(pingPin, HIGH);
  noInterrupts ();
  cm = microsecondsToCentimeters(duration);
  interrupts ();
  delay(50);
}

long microsecondsToCentimeters(long microseconds)
{
  return (microseconds / 29 / 2);
}

// function that executes whenever data is requested by master
// this function is registered as an event, see setup()
void requestEvent()
{
  Wire.write(cm); 
}

I've made "cm" a global variable, so you can access it in requestEvent. There is still the issue that Wire.write will only write a single byte. That will be OK if the number of cm is an integer (no decimal places) and is in the range 0 to 255.