Serial.read() function reading additional data

Projects Networking, Protocols, and Devices
1

Hello everyone,

So I just got my first Arduino yesterday and have been trying out hello world kind of applications on it (I got an Arduino Uno).

I decided to try out the serial functionalities of the board. I wrote the following code:

void setup() {

  Serial.begin(9600);
  
}

void loop() {

  while(Serial.available() == 0); // Waits for serial to be available

  int x = Serial.read(); // Reads an input

  Serial.println(x);
  
}

I then ran this code and everything was compiled and uploaded fine.

However every time I input a number (from 0 to 9), the number 10 gets printed on a new line.

Here is an example:

  • Input: 1

Output: 49 // This one is expected, it's the decimal value of the char '1'
10 // Where does this come from?

  • Input: 2

Output: 50
10

  • Input: 3

Output: 51
10

I then tried to print a normal String using the Serial.print("Hello") but this time everything was printed right.

Does anyone know where this problem comes from? I have no idea.

Thanks for your help.

2

The 10 is coming from the Line Feed Character that's being sent by the serial monitor.

What you should do instead is change Serial.println(x); to Serial.write(x); and you should be good to go!

3

Thanks a lot

4

Have a look at the examples in Serial Input Basics - simple reliable ways to receive data.

...R