Minor updates to examples

examples/SFRRanger_reader/SFRRanger_reader.ino

   Wire.requestFrom(112, 2);    // request 2 bytes from slave device #112
 
   // step 5: receive reading from sensor
-  if(2 <= Wire.available())    // if two bytes were received
-  {
-    reading = Wire.read();  // receive high byte (overwrites previous reading)
+  if (Wire.available() >= 2) { // if two bytes were received
+    reading = Wire.read();     // receive high byte (overwrites previous reading)
     reading = reading << 8;    // shift high byte to be high 8 bits
-    reading |= Wire.read(); // receive low byte as lower 8 bits
+    reading |= Wire.read();    // receive low byte as lower 8 bits
     Serial.println(reading);   // print the reading
   }
 

examples/Scanner/Scanner.ino

 
 
 void setup() {
+  // uncomment these to use alternate pins
+  //Wire.setSCL(16);
+  //Wire.setSDA(17);
   Wire.begin();
   Serial.begin(9600);
   while (!Serial);        // Leonardo: wait for serial monitor

examples/master_reader/master_reader.ino

 
 void setup()
 {
-  Wire.begin();        // join i2c bus (address optional for master)
-  Serial.begin(9600);  // start serial for output
+  Wire.begin();             // join i2c bus (address optional for master)
+  Serial.begin(9600);       // start serial for output
 }
 
 void loop()
 {
-  Wire.requestFrom(8, 6);    // request 6 bytes from slave device #8
+  Serial.print("read: ");
 
-  while(Wire.available())    // slave may send less than requested
-  { 
-    char c = Wire.read(); // receive a byte as character
-    Serial.print(c);         // print the character
+  Wire.requestFrom(8, 6);   // request 6 bytes from slave device #8
+
+  while(Wire.available()) { // slave may send less than requested
+    char c = Wire.read();   // receive a byte as character
+    Serial.print(c);        // print the character
   }
 
+  Serial.println();
   delay(500);
 }

examples/master_writer/master_writer.ino

 
 void loop()
 {
-  Wire.beginTransmission(8); // transmit to device #8
+  Wire.beginTransmission(9);  // transmit to device #9
   Wire.write("x is ");        // sends five bytes
-  Wire.write(x);              // sends one byte  
-  Wire.endTransmission();    // stop transmitting
+  Wire.write(x);              // sends one byte
+  Wire.endTransmission();     // stop transmitting
 
   x++;
   delay(500);

examples/slave_receiver/slave_receiver.ino

 
 void setup()
 {
-  Wire.begin(8);                // join i2c bus with address #8
+  Wire.begin(9);                // join i2c bus with address #9
   Wire.onReceive(receiveEvent); // register event
   Serial.begin(9600);           // start serial for output
 }
 // this function is registered as an event, see setup()
 void receiveEvent(int howMany)
 {
-  while(1 < Wire.available()) // loop through all but the last
-  {
-    char c = Wire.read(); // receive byte as a character
-    Serial.print(c);         // print the character
+  while(Wire.available() > 1) {  // loop through all but the last
+    char c = Wire.read();        // receive byte as a character
+    Serial.print(c);             // print the character
   }
-  int x = Wire.read();    // receive byte as an integer
-  Serial.println(x);         // print the integer
+  int x = Wire.read();           // receive byte as an integer
+  Serial.println(x);             // print the integer
 }

examples/slave_sender/slave_sender.ino

 
 #include <Wire.h>
 
+int led = BUILTIN_LED;
+
 void setup()
 {
+  pinMode(led, OUTPUT);
   Wire.begin(8);                // join i2c bus with address #8
   Wire.onRequest(requestEvent); // register event
 }
 // this function is registered as an event, see setup()
 void requestEvent()
 {
-  Wire.write("hello "); // respond with message of 6 bytes
-                       // as expected by master
+  digitalWrite(led, HIGH);  // briefly flash the LED
+  Wire.write("hello ");     // respond with message of 6 bytes
+                            // as expected by master
+  digitalWrite(led, LOW);
 }