Writes binary data to the serial port. This data is sent as a byte or series of bytes; to send the characters representing the digits of a number use the print() function instead.
Serial.write(val) Serial.write(str) Serial.write(buf, len)
Arduino Mega also supports: Serial1, Serial2, Serial3 (in place of Serial)
val: a value to send as a single byte
str: a string to send as a series of bytes
buf: an array to send as a series of bytes
len: the length of the buffer
byte
write() will return the number of bytes written, though reading that number is optional
void setup(){ Serial.begin(9600); } void loop(){ Serial.write(45); // send a byte with the value 45 int bytesSent = Serial.write(“hello”); //send the string “hello” and return the length of the string. }