Serial.readString()

Description

Serial.readString() reads characters from the serial buffer into a String. The function terminates if it times out (see setTimeout()).

Serial.readString() inherits from the Stream utility class.

Syntax

Serial.readString()

Parameter Values

  • Serial: serial port object. See the list of available serial ports for each board on the Serial main page.

Return Values

  • A String() read from the serial buffer

Example Code

void setup() { Serial.begin(9600); // opens serial port, sets data rate to 9600 bps } void loop() { // check if data is available if (Serial.available() > 0) { // read the incoming string: String incomingString = Serial.readString(); // prints the received data Serial.print("I received: "); Serial.println(incomingString); } }
  • Type "HELLO" on Serial Monitor and click Send button:
  • COM6
    Send
    Autoscroll Show timestamp
    Clear output
    9600 baud  
    Newline  
  • The result on Serial Monitor:
  • COM6
    Send
    I received: HELLO
    Autoscroll Show timestamp
    Clear output
    9600 baud  
    Newline  

※ NOTES AND WARNINGS:

  • Serial.readString() may read a single incoming string in multiple times (resulting in multiple fragments). To read a single string at one time, use Serial.readStringUntil() with delimiter instead.
  • Serial functions are not only used for the communication between an Arduino board and Serial Monitor of Arduino IDE but also used for the communication between:
    • An Arduino board and other Arduino board
    • An Arduino board and other sensors/devices
    • An Arduino board and computer (any Serial software on computer)

See Also

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Arduino UNO R3
Arduino Starter Kit
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