Serial.print(data)

Description

Prints data to the serial port.

Parameter

data: integer types, including char, floats
Printing of floats is supported with a precision of two places to the right of the decimal point.
This may change soon.

Syntax

This command can take many forms:

Serial.print(b) with no format specified, prints b as a decimal number in an ASCII string. For example, 

int b = 79;
Serial.print(b);

prints the ASCII string "79".

Serial.print(b, DEC) prints b as a decimal number in an ASCII string. For example, 

int b = 79;
Serial.print(b, DEC);

prints the string "79".

Serial.print(b, HEX) prints b as a hexadecimal number in an ASCII string. For example, 

int b = 79;
Serial.print(b, HEX);

prints the string "4F".

Serial.print(b, OCT) prints b as an octal number in an ASCII string. For example, 

int b = 79;
Serial.print(b, OCT);

prints the string "117".

Serial.print(b, BIN) prints b as a binary number in an ASCII string. For example, 

int b = 79;
Serial.print(b, BIN);

prints the string "1001111".

Serial.print(b, BYTE) prints b as a single byte. For example, 

int b = 79;
Serial.print(b, BYTE);

returns the string "O", which is the ASCII character represented by the value 79. For more information see the ASCII table.

Serial.print(str) if str is a string or an array of chars, prints str as an ASCII string. For example, 

Serial.print("Hello World!");

prints the string "Hello World!".

Parameters

b: the byte to print, or

str: the string to print

Returns

None

Example:

/*
Uses a FOR loop for data and prints a number in various formats.
*/
int x = 0;    // variable

void setup() {
  Serial.begin(9600);      // open the serial port at 9600 bps:    
}

void loop() {  
  // print labels 
  Serial.print("NO FORMAT");       // prints a label
  Serial.print("\t");              // prints a tab

  Serial.print("DEC");  
  Serial.print("\t");      

  Serial.print("HEX"); 
  Serial.print("\t");   

  Serial.print("OCT");
  Serial.print("\t");

  Serial.print("BIN");
  Serial.print("\t"); 

  Serial.println("BYTE");

  for(x=0; x< 64; x++){    // only part of the ASCII chart, change to suit

    // print it out in many formats:
    Serial.print(x);       // print as an ASCII-encoded decimal - same as "DEC"
    Serial.print("\t");    // prints a tab

    Serial.print(x, DEC);  // print as an ASCII-encoded decimal
    Serial.print("\t");    // prints a tab

    Serial.print(x, HEX);  // print as an ASCII-encoded hexadecimal
    Serial.print("\t");    // prints a tab

    Serial.print(x, OCT);  // print as an ASCII-encoded octal
    Serial.print("\t");    // prints a tab

    Serial.print(x, BIN);  // print as an ASCII-encoded binary
    Serial.print("\t");    // prints a tab

    Serial.println(x, BYTE);    // prints as a raw byte value, 
    //                             then adds the carriage return with "println"
    delay(200);            // delay 200 milliseconds
  }
  Serial.println("");      // prints another carriage return
}

Programming Tips / Known Issues

Serial.print() doesn't work on floats, so you'll need to cast them to an integral type, losing any fractional values. It is sometimes useful to multiply your float by a power of ten, to preserve some of this fractional resolution.

Be careful about doing math inside the brackets e.g.
Serial.print(x-2, DEC);
The unsigned char data type, and byte data type will yield incorrect results and act as though they are signed types i.e. type char.

The Serial.print function puts data into a buffer. It will wait for one character to send, before going on to the next character. However the function returns before sending the last character.

See also

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